It's because people have seen too much evidence of Ole not being willing to change things in these kind of games
It's because there's a group of posters who already made their minds up long ago that Ole isn't up to it, and who's reinforced that belief by repeating it online and defending it against all comers for so long that they've long since gotten out of the habit of questioning themselves. When things go well they're silent, when they don't they're off the mark immediately, and against a diminishing crowd of opposition because there's only so long people can stomach engaging in pointless discussion with people who generally only see what their preconceptions tell them is there.
It's important of course to avoid falling into the opposite trap too. The way this team has been evolving over the past couple of seasons, it's frankly absurd to talk as if there's any sort of case for seeing the manager as inadequate, but also it is not yet at its end destination, and no one can take it for granted that OGS will get us there. I think it's annoying that it's really not possible to have a reasoned discussion about worries and shortcomings in games like Southampton (there were more than a few) because it's just drowned out by an incredible amount of hyperbole and nonsense that has nothing to do with the game and everything to do with people seizing on it to go "There! That's what I've been saying for a year now!".
But if we have 5-10 games where we play like that this season, we're not going to challenge for a title, that's for sure. We might get away with a handful, and sometimes we'll get the points anyway, but it's looking like it's going to be a really tight 4-team race and chances are at least one of the other three is going to deliver consistency.
What I found most worrying against Southampton vis-a-vis title-challenging credentials was the lack of urgency and ideas in the final 10-20 minutes, in such marked contrast to the dominant football they delivered for the first 20 minutes or so of the second half. It's like they shoot their bolt, and when it's shot it's shot, and they lapse into acceptance that this is how it's going to end up. It's hard to tell what's the reason for that, and fortunately there are also many examples of the opposite, but again that's the sort of thing they can't do more than very occasionally if they're going to have a chance.
And, expectations are different this year. Last season, it was still about continuing improvement, you accepted that there would be setbacks and games like this didn't worry me too much. But now, performances like this is a standard we can't afford to drop to more than very occasionally. It really brings across the magnitude of the challenge we're up against, and what it actually means to take the step from being a really promising team on a good development curve, to actually being a contender.