To think you shouldn't join a committee if you haven't the time?

[Vintagejazzing]

I'm on two local committees. Both of them have sufficient members but we throw it open to the group at our AGM for anyone else to put themselves forward. On both groups we have someone who voluntarily put themselves forward and in one case put themselves forward again this year, but who simply don't have the time to contribute meaningfully.
One person regularly objects to the time we choose to hold our monthly meeting, saying they're not free because it's their golf night, but no Thursday is the night they babysit for their grandchild and no, Friday doesn't suit either because they go to their house down the country, and afternoons are difficult because....... No matter what time we pick it's difficult and a fuss is made, and they either arrive late and we have to recap on everything, or they leave early so we have to move the agenda around to suit them.

On the other committee the person rarely attends meetings because they're too busy but then questions and queries everything on the minutes, wants decisions changed etc etc.

AIBU to think joining a Committee that you've no time to take part in is just being a time wasting nuisance for everyone else?

100%. Ditto volunteering that needs training, doing the training then never quite having the time to do the actual volunteering.

You could alter the process to produce an agreed job description with an outline of minimum expectations to avoid this in future, this works well in a group I am in.

Worse are those who update their linkedin profile weekly with a load of nonsense loosely based on having caused chaos in committee and done nothing positive.

I totally agree. We had this problem with the school governors. Several people joined then moaned that they could never get to the meetings (which were always in the evening, and the timing of which they knew before joining). The reason given - they were 'professionals', said in such a way that suggested if you were able to make the meeting, then your job clearly wasn't important, and you weren't a 'professional'.