Does this bother you? About FB groups.

[LindorDoubleChoc]

I'm on a FB group to do with a particular hobby.

It's quite busy, many posts per day.

There are one or two members who post every single day, without fail, about other interests of theirs. Usually a bunch of photos and comments about what they have been up to. Nothing to do with the "theme" of the group.

I scroll past.

But I find it slightly irritating. I'm guessing this is a failing in me? But why do they do it?

Yes - similar to people ruining linkedin
linkedin is for business.
but these days people post “I’m so proud of my son learning to ride his bike”bla bla

Yes it's annoying - as if they need the attention

Similar on my FB hobby group page - usually newer people signing up who don't know the etiquette. Luckily, the admins are pretty active and take down the posts with a gentle reminder.

Edit: I've no idea why but I think the pp who mentioned attention seeking is probably right.

Groups vary according to how tolerant they are of off-topic posts. Join one where the culture is only on-topic posts, or in which admin delete anything not strictly on topic.