When they say “they sold” it means there was higher selling pressure than the buying pressure and this usually makes the price to plummet. In this case most buyers are not willing to buy at a fair price but would rather at lower prices and most will actually place lower buy orders.

Imagine you and 100 other people bought cars at $80,000 but then one day you desperately need some money, you decide to sell it at the same price but no one is willing to buy. Instead, there are some people offering you $60,000 which you immediately accept. Now all of a sudden the market price of the car is at $60,000 and very few will be willing to buy it at $80K due to the trend (Thus you and the 100 others sold and made the price “dump”)

The same happens with “they bought” leading to a price pump

When you go to an exchange, there are two lists, one for the sellers and one for the buyers. Think of it as an entry on a marketplace, you post that you want to either buy or sell a certain amount of BTC and you put the price for it.

The entries remain there until someone accepts the deal posted.

As you can see, there's a clear difference between buying and selling, even though there's always a buyer and seller on each transaction.

The market needs to have both buyers and sellers but depends on which phase like bullish or bearish, buying and selling demand balance will be skewed towards either buying or selling.

If it leans towards selling and there is FUD to create panic in the market, price will fall or even worse crash. It is because buyers are smart and will remove their previous buy orders and whales remove their buy walls for moving it to deeper prices. As said sellers are in panic and have to set up new sell orders at much lower prices. Additionally, we must know that there are liquidation on the market against sellers too.

The news of someone or an organisation selling Bitcoin gains more publicity because fudsters promote it on different platforms. Anyway, the Bitcoin market is also driven by the law of demand and demand. When more people are in the market to sell, the price drops, and the news is everywhere that there is a sell-off. But we also used to have threads that discussed buying.

Does the concept of hodling mean keeping your Bitcoin forever? People will have plans of how long they want to hodl and when they intend to take profit. Truthfully, hodling Bitcoin for a long time is the real deal.

For every sale there must be a purchase.
But when it comes to Bitcoin, it's not entirely correct to use the terms 'buy' and 'sell'.
Bitcoin is money , a form of digital peer-to-peer cash , and money itself cannot truly be bought or sold.What we're actually doing is converting Bitcoin into other forms of money and vice versa.So instead of calling it a 'sale' or a 'purchase', it's more accurate to call it a conversion
Bitcoin doesn’t have a price, because money doesn’t have a price.
Money only has an exchange rate.
Just like we don’t say 'the price of the euro is $1.10', we say 'the exchange rate between the euro and the dollar is 1.10'.
Bitcoin is money, shouldn't be treated like some stock or commodity with a price , it should be viewed as a monetary unit with an exchange rate relative to other currencies.
Using terms like 'buying' and 'selling' Bitcoin sends the wrong signal , it reinforces the false idea that Bitcoin is just some asset or stock.
But Bitcoin is money. You don’t 'buy' money , you exchange one form of money for another.
So when people say 'I bought Bitcoin', what they actually did was convert fiat into Bitcoin.
This misunderstanding shows how far we still are from truly grasping what Bitcoin is

I am not going to lie, this a very logical question from OP which must users actually don't understand the point he is coming from.

To my ideal, buying and selling of Bitcoin evolves around in a trade marketplace of the Blockchain.

First push of Bitcoin to be in used or circulated in an exchange or any Blockchain network to be bought comes from the miners as rewards earned for mining new blocks.
So as you may know, they don't buy it but earns it as rewards and then sells it at their own please of time which in speculations the buyers becomes more notable.

So I guess OPs worries with his expression is due to the fact that there is always speculative news whenever any of the institutional investors buys Bitcoin to their portfolios but since I am not an insider of the ETF Financial Management Firms, I will only speak unsure so why the phrase "Buy and Bought" of BTC is more noticeable in the air is because, most of the instituional investors buys directly from miners who earns large scale of BTC mining rewards through the process of OTC.

So, they (miners) opens the market for trading and exchange in the Blockchain network.
And higher buying volumes becomes more in speculations for investors and OP and the rest of us get skeptic about who is selling such high volume as non of the whalers or instituional investors with their high holdings are not agreeing of selling yet. So it becomes a worry of who is selling but all we hears is who are buying.

However, there are also retailers who are accumulating Bitcoins with their minimal amount of buying and are hodling in the long term. So, whenever they tend to sell, it is usually of a higher volume which booms about the attractions of the buying order.

That is just to my best of ideal about how the trading market revolves.

You sell when you feel that your goal has been reached - otherwise, why do it?

This is called market sentiment. The question is who triggered the transaction?. If the transaction was triggered by the selling party obviously market will dump. This is because the seller is giving out at the nearest available offer. But when the transaction is triggered by the buyer, there are chances of comparing offers to get the best suitable offer and this triggers pump.

E.g Two kids playing on the rain and one said he wants to trade his toy for some snacks and the second kid agrees to it, establishing a deal,  the first one is losing the exact value for the toy and the second is getting a toy at a good offer, but will obviously not have good value for that toy because it came too cheap. This explains an aggressive and passive investor, the urgency in the sell order triggers what happens next in the market.

If someone is selling, there's always someone buying. Media coverage always has a psychological impact on the market. While the media's influence can sometimes be positive, they often aren't objective, especially when reporting on sales. When large companies sell, there's a sale news story, but when individual users sell, it's less newsworthy, so we might be experiencing this situation