Here in our country, people are not that well informed about digital currencies, but eager to earn especially on easy money.
Sadly some schemers use bitcoin as an investment opportunity that targets greedy people that enters with the promise of huge  profit without even knowing what they are in to.
Greedy people make Bitcoin Categorized as scam.

BTC has been hot topic across the globe and you are saying that most of people think it as a scam. I disagree with your statement, the popularity is increasing and this digital payment ecosystem has amassed many of them.

In my opinion we can't change such negative minded people but those who invested before years are millionaires today what about them? I understand people need to be well educated regarding BTC and how it works else it would have reached its peak.

Most people? You mean those who doesn't have knowledge about Bitcoin. One of the reason why they thought it is a scam because of the investment scheme that use bitcoin as their front of payment.

 If you know someone who think that way please educate them.

Most of them that brought by those ponzi scam projects who used bitcoin.

Giving them much clearer ideas about this system will open up their minds that it isn't a money generating
tool, It's needs a lots of skills and knowledge before they understand that part, and with the usage, bitcoin
is a currency that's already being used for transacting online.

That's certainly true, mate. Most people lack education about everything related to Bitcoin and Blockchain tech. If they knew Bitcoin's potential to transform mainstream finance, they wouldn't think it is a scam. They're most often guided by what's said on mainstream media and the elites (like Warren Buffet). Since these entities talk negatively about Bitcoin most of the time, people become skeptical about it. Rest assured that with COVID-19 encouraging digital payments adoption at a large scale, more people will become inclined into using Bitcoin and other cryptocurrencies for their daily lives. I think some time is needed for the crypto space to mature. It's been only 11 years since Bitcoin's inception, with progress made in every level. Already, some governments are recognizing Bitcoin as legal tender. We might reach a point where people will distance scams from Bitcoin itself in the not-so-distant future. Remember, patience is key in order to achieve great results in the long term.

Nonetheless, it's our duty as crypto enthusiasts to let the world know that there's an alternative to the current monetary system. As long as people are educated about Bitcoin, they'll surely use it alongside Fiat for mainstream transactions. Back then, Bitcoin was declared to be dead hundreds of times. But day after day, it's been showing quite the opposite. Bitcoin has been growing at a fast pace ever since it came into inception back in 2009. The 2017 bull market run has only accelerated its adoption. Someday, people will stop believing misinformation spread throughout mainstream media, as they become more knowledgeable about the subject. Just my thoughts

it seem it is very hard to convince some people and have them change their mind from their previous believe on btc probably because of the high volatility associated with btc and crypto in general, 
and also the fact that btc does not have any physical value attached to it except being a digital payment system, i guess it is still very strange to some people how the price manage to rise to this extent.

Because they heard the two words "Bitcoin" and "Scam" together much often so they consider bitcoin is the scam.

Literally 90% if the people in this world don't know the inflation so it is not possible for them to understand decentralization, peer to peer transactions.

Many people just assume up front without knowing the background of bitcoin, it's usually people who have never been in crypto. so they say bitcoin scam, scam or something. so we can only ignore what people say, because in reality bitcoin is not a scam as many people are talking about

And guess who are the people peddling those ideas? Lazy people who got scammed because they believed about a certain easy money scheme. Its their own mistake but they are blaming the technology for it. They didn't spend some time researching or reading before spending money. Kind of sucks that its very easy for them to spend money than spending time researching.

Those people who are spreading rumors that btc is a scam are the very same people who doesn't even understand btc and crypto.

They did not know that free money and easy money can make them vulnerable to scammers. Yes there are many scammers in different social media platform and the victims are usually the people who are seeking easy money. There is no easy money because you really need to exert effort and time in order to make gains in a specific investment. Do not also believe in rumors, exert effort in order to know if it is legit or scam.