I'm not sure why but I still find Bittrex as one of the best exchanges out there, especially when one single exchange (Binance) is trying to take over the whole crypto industry. I keep supporting Bittrex because I personally feel horrible seeing Binance destroy the coins of their choice and CZ thinking so lordly (he literally wished to reorganize the BTC chain recently). I don't think that Bittrex has ever been hacked since its creation, which is a very positive point for its reputation. Moreover, all (or maybe most of?) those complaints that were registered under the feedback of that profile that you shared seemed to have one single problem: unavailability of KYC when it was requested by Bittrex (I know that it wasn't very ethical of Bittrex to just ask for KYC out of nowhere, but you need to be ready for this sort of stuff when you're using a service registered in the US). Those who were willing to provide their verification documents never faced any issue(s) with Bittrex AFAIK; I'm one of those.

I just do not want CZ to have complete control over this whole industry, that's all. Let's keep some competition among exchanges alive!

This is true but there is also another apsect, according to Raja_MBZ Bittrex is an excellent exchange that he never ever had issues with, just a few people come here to post negative things about Bittrex but on the whole it seems pretty solid exchange to me.

Does anyone know why this U.S. citizen prohibition thing happened?
Kind regards
https://bittrex.zendesk.com/hc/en-us/articles/360028996652-Market-Availability-Changes-for-U-S-Customers-6-21-19

i feel the same about Binance mainly because they keep creating centralized tokens and dump on their customers! and also because of their DEX which is anything but decentralized.
but Bittrex is still dishonest because of  what they did. it is not just about verification but because they blocked accounts of thousands of people because they were coming from certain countries and that meant that they practically stole millions of dollars worth of cryptocurrnecies from these users. note that they had absolutely no issue with people from these countries before and this rule was applied overnight without warning and their accounts were closed without letting them verify or anything.

They're most likely caving to US regulatory pressure, I think all the blocked coins/tokens/whatever had ICOs and have little to no real utility, and therefore there's a high likelihood they'll be treated as securities by the US SEC, which means it's either not possible or it requires more red tape to allow so-called unaccredited investors buy or sell them.

After Binance, Bittrex ain't looking good for the US traders either:
~snip~

That means Bittrex also closing the doors for the US traders! Bittrex getting rid of certain alts, at that point where are US traders going? Binance launching binance.us for US customers, hoping that Bittrex will be announcing more details on regarding this.

It is same pattern that was seen when cryptopia suddenly went "legit" and delisted a lot of coins.

Its been quite sometime when I last used my Bittrex account and only today when I opened my account to see how my alts are doing, I was surprised to see that my account was disabled. I didn't receive any notice, warning or whatsoever coming from Bittrex about their actions to my account and I find it unfair on my side for not notifying me. I already filed a support ticket and waiting for their positive response.