Weird ELO distribution for top 10 winners of tournament


the beginners often get many ofter weak players as pairings, somits easy to get many wins. If i participate, i often get 2000s, so its difficult to get fast wins.

You played in an arena tournament. In that format you get paired by rating.
https://support.chess.com/article/335-what-are-arena-tournaments
As others have pointed out, it is common (whether it is "fair" or the "best" way is personal preference). Think of it like a handicap in golf so that players of a wide variety of skill can still compete against each other fairly. One problem that arises with this is "sandbagging" where a strong player intentionally drops rating to play against weaker opponents. I believe Chess.com has a way to detect this though