It's not necessarily an opposite action though to be fair. The post you were replying to referenced staying silent, which isn't really the opposite of giving encouragement. I don't agree with booing and heckling and the general abuse of individuals regardless of how they play, but much of what people are talking about in here is just every day moaning and groaning.
It's not easy to just politely clap the 30th misplaced pass your central midfielder has played when you're chasing a goal, there will inevitably be howls of frustration. It's like dealing with your kids in a way, the first couple of times they do something wrong you calmly say 'Don't do that please buddy' but when they do it for the 10th time you're shouting 'HOW MANY TIMES HAVE I GOT TO TELL YOU you horrible freeloading little tw…' sorry I've lost my train of thought. Anyway, it's just human nature.
There's lots of grey areas in between the two general points of view in here for sure.
If it's an hour in and the crowd are behind them as I've mentioned and some useless prat in midfield is wasting all our possession then I can understand a crowd reaction. Everybody will want a change made....and now.
If it's 5 mins in and somebody's messed up a simple pass then I don't see the point of screaming abuse at them.