I hide ones with a certain word in every title also, but not "lighthearted".
I know what you mean though. I don't find it naff, I find it sad that people feel they have to apologise for their venting and mock outrage because they know the handful of mumsnetters are going to came along and call them names for complaining about their husbands or whatever.
I wish we could hide those small minded never changing mumsnetters comments (it's always the same few) because they remind me of my MIL!