Because most of them aren’t proper supporters and need someone feeding them opinions so they can talk about the game at work on Monday.
Of course, if they were proper supporters they'd know you can just go with a few stock phrases and get through pretty much any post match discussion without watching it at all.
We played well in parts
I thought your lot could have got more out of the game
We've played far worse teams this season
Solly played well
We should have done better with the chances we had
Needed somebody faster than Gross on the end of that pass
I didn't think it was a penalty [to be said regardless of whether there were any serious penalty appeals for either side]