It is quite frankly a stupid decision not to include PC in the crossplay environment, and every argument I see about console players not wanting to get stomped by PC players ignores a basic facet of the game: there is skill based matchmaking.

If you're getting stomped by PC players, they will simply get a higher skill rating than you and no longer be in your lobbies. You will instead get lower skilled PC players that are level with your ability, despite any advantages they may have. Sure, you may be a console diamond and be even with a PC gold, but if you guys are roughly equal in your ability to kill one another, who cares? With the massively increased player pool crossplay could offer, this SBMM would do a much better job of filling lobbies with evenly matched players.

They had an opportunity to address a lot of the problems people experience in matchmaking, particularly on PC (unable to join duos, LTMs, or have proper ranked matchmaking) but are choosing not to for some reason. Reading a lot of the replies in the announcement, that reason very well may be players failing to understand how matchmaking works and that it won't change the skill level of people that are actually in their matches; if anything, it would reduce the amount of much better players they have to face.