At another site they allow non members to play given a 1500 rating no matter how bad. I am sure that helps to inflate their numbers.
Does chess.com have the toughest pool of players?

Trouble is, we have no idea what those numbers are because we have no idea how long the stick is.

Unless you're a super-GM it doesn't matter. There will be lots of people at your level on any major site.
The only time it would matter is if you're one of the very top GMs in the world; in that case, you might find more opponents at your level at one site than on another. But even then, it might vary at different times of day, if some top GMs regularly come online at one site at one time of day and others come online at another site at another time of day. In that case, you might decide where to play based on who tends to be online where at the time you want to play.
But for 99.99% of people, it simply doesn't matter. There will be lots of people at your level on any major site.
Hi there, I know that other site mentioned, and I had a good run there, until my health issues started . I caught myself, but in the end I found myself reporting many of my Opponents, and some got blocked, but when they stopped answering my queries I decided to open a new account there, and I could get back to my peak rapid rating anymore, here on chess.com i cant even reach 1800 on the li site i was rated around 2000 in rapid....

I play on other sites and my rating is easily 100-200 points higher there compared to here.
Ratings here are very deflated whereas other places it's quite inflated.
I can only assume that chess dot com has the toughest players.

The best guess is that there is no reason to believe in any generalized bias, and that the law of large numbers means that the players should be roughly equal. Anything else is just reckless speculation.
I have any idea: let’s argue about how many angels could dance on the head of Danny Rensch.
Seems to me that quite a few titled players regularly play here. That will have a way of bumping up the competition.

Of course, but they might interact with the 2200 - 2300 crowd, who in turn interact with the 2000 - 2100 crowd... contact with stronger players will accelerate your own development, IMO.

Different sites have very different rating pools. If one site starts everyone at 1200 and another starts everyone at 1500, one would expect to be rated 300 points higher on the second site. That would indicate nothing about the difference in quality of play between the two sites or the difference in the prevalence of cheating. It would be driven purely by the different initial ratings driving a different mid-point in the rating pool.

Ratings are only useful for comparison with other players in the same rating pool. That's how rating systems work. 1200 doesn't mean anything. Neither does 2000. People who play both USCF and FIDE-rated events have ratings in both systems that are not identical; some of this is due to random statistical noise, but also they are different rating pools that are not perfectly in line with each other.
I could start a new site that gave everyone an initial rating of 0. Weaker players would soon have a negative rating in the range -600 to zero, while GMs would be 1400-1800. Or I could start everyone at 3000; weak players would soon be rated 2400-3000, while the very top GMs might push toward 4800.
There is nothing in the rating system that means a particular quality of play will result in a 1200 rating. Rather, it's your performance against other players that leads to your rating. If everyone starts at 1200, that will lead to 1200 being the long-run mid-point of the rating system (assuming no inflation or deflation in the rating pool over time). If everyone starts at 1500, that will lead to 1500 being the long-run mid-point of the rating system (again, assuming no inflation or deflation in the rating pool).

According to percentiles... no. Ratings are just useful for relative comparison to others in the SAME pool of players. Ratings are harder on chess.com while the actual percentiles on its main competitor are definitely harder. Not sure why that is.

If you're rated below 2800 FIDE, it simply doesn't matter. You will find many opponents at and above your rating level on any major sites.
If you're deciding where to play, there are issues that are more relevant to your decision. But that gets into comparisons with competitor sites, which is not permitted on chess.com. Chess.com is a good site; if you want to discuss comparisons, reddit would be a good place for that conversation.
Answering OP’s question - no. I don’t think so. I’ve played over 1000 blitz games now on both chess.com and its main competitor, and my percentile ranking is 10 percentage points lower over there. Forget about trying to cross compare the ratings - that’s a meaningless, but the percentile is informative. Either their pool is generally stronger, or it is saturated with cheaters that don’t get caught/booted.