I disagree. My opinion obviously, but I remember, back in the early days of console online gaming (and horrible match making) playing a map designed for 32 player with 5 total. Sure you can get some funny moments at times but it feels dead and most times people will quit and go to a populated game. Bot backfill and casual modes are IMO great additions to maintain the pace of match. They need some tweaking on their responsiveness and laser accuracy of course but I'd rather play with bots than ran around looking for 2 players.
Maybe I'm just an older gamer now and can't be bothered to care about the posturing or gatekeeping people consistently do to feel better about themselves in an online environment.