Not sure whether to wade in or not really! So why not!
I love kids - and am happy to see them in cafés etc. however there is a balance - and kids running around climbing on furniture/disturbing others isn't great (unless in an area designed for that!). It should be possible for everyone to co-exist with some consideration. The same as any other situation - like not speaking loudly on a phone in a cafe or one person sitting at a table for 4/6 or tutting just because someone is trying to get past with a pram (or whatever our individual irritants are).
Equally we all have bad days where we don't act quite as well as we probably should - and people get very cross/irritated very quickly. I think we should just aim to be nicer to each other!