Zirkzee got booed once and dozens of people on the caf lost their shit over it. Cue the thread named 'we have the worst fanbase in the world' getting pages and pages of comments in the aftermath, where our fanbase was collectively labelled as toxic due to a few seconds of booing.
Yet when we applaud the players for earning a 1-1 draw vs the 2nd best team in the country, now we're part of the problem for allowing standards to slip? Unless you think we should be booing every single performance until the club is back to fighting for major honours, then the alternative is that there will be some warm applause from the fans on a matchday. That doesn't mean that we think our current league position is acceptable.
Matchgoing fans have very little influence over the long-term direction of the club, so we'd generally prefer to support our players under most circumstances. Sure, we're dissatisfied with being 14th, however if we were to regularly boo the players off the pitch in an attempt to 'raise standards', then it would achieve very little other than making the weekly trips to Old Trafford an even more depressing experience for everyone involved.