First of all there are no animations on the sidebar and chess.com needs fide rules because yesterday I read in forum past stating that chess.com uses USCF rules because fide rules are difficult to code. On the other hand lichess uses fide rules and the famous chess nerd said that chess.com is a American website so it uses USCF rules and lichess is French website so it uses fide rules.
If a chess.com moderator sees this forum post please add fide rules to chess.com.
Moderators don't do development.
That said, the main thing that isn't similar to FIDE is sufficient material to mate on timeout rules. It's not harder really to program that, just the code is a bit more complex but certainly doable. However, it's also a philosophical decision and one that was decided made more sense to be more similar to US Chess where help mates are not considered, only if the mate can be forced.
First of all there are no animations on the sidebar and chess.com needs fide rules because yesterday I read in forum past stating that chess.com uses USCF rules because fide rules are difficult to code. On the other hand lichess uses fide rules and the famous chess nerd said that chess.com is a American website so it uses USCF rules and lichess is French website so it uses fide rules.
If a chess.com moderator sees this forum post please add fide rules to chess.com.