I'm concerned you don't even understand the situations where people suggest "it's still early". The most common scenario is early in the season when the Jays lose a few games. Maybe someone in the bullpen blows the game, or a starter lays and egg or the offense is MIA. Some Jays fans are upset that they lost and these events happened and they suggest change is needed. Cut that player, bench him, trade that guy, change the lineup, fire the manager, etc. They often look at SSS results (which are wayyy more evident early in the season as hitting and pitching stats can be skewed early in the year) to defend their positions and argue the team should start making changes right now because every win matters and obviously the players with s***** results so far suck and should be replaced. If the same player goes into a slump in August, those same fans typically don't even notice it.
Rational fans understand it's really stupid to make rash/significant changes based on a SSS and that you need to stay the course for a longer period. You don't want to start cutting/losing assets on your 40 man roster that you may need over the course of a 162 game schedule. That's where the "it's still early" argument comes from. I also don't understand how this is so difficult to understand. It literally has nothing to do with the importance of winning games in April/May - obviously everyone wants to get off to a good start and those games do matter, but you don't make wholesale changes if you start the year 7-12.
That said - will you sometimes come upon the situation like we have with Manoah where removing the 2022 Cy Young finalist from the rotation after 4 starts would have actually been the right decision? Of course you do - and of course this happens more often with fringe players like Anthony Bass or Cimber and such. But this is very difficult to predict and often if you're talking about a player with a proven track record, the early season slump is often countered with a hot streak as they revert back to the career norm.
I hope this helps.