I've heard commentators say that, but they're not ex players.
I would agree that there might be times in a game where fans need to give their team a lift. We've seen it with Wales and singing of the national anthem in particular. That certainly doesn't happen with Cardiff City (and probably lots of other club sides). I think, in our case, it's nothing to do with a half empty stadium, but the feeling of "here we go again".
I wasn't at the Ipswich game due to illness. I wonder if the atmosphere was better then?