I can empathise.
I've not known anyone talk about this/mention it in conversation quite like this before though, BUT have known quite a few people though who find that people start avoiding them/friendships end because of difficult times and life events, and have heard a lot of people talk about this.
Eg- A friend I'm thinking of (her child died) found that many people she hadn't been in touch with for years came out of nowhere and wanted to try and help/ be in touch with support etc. It was overwhelming in a good way (for her I mean, but I wonder if some people would see this as pity friendship?). Several friendships were rekindled for her, directly because of a terrible tragedy.
But she felt very upset about one or two good friends of hers who seemed to disappear at the time, and were not in touch very much. She felt very let down by them.
The thing is, I know at least one of the people she fell out with (because of this) was going through an extremely difficult time herself (very severe health problems and other awful major life events), and she gave as much as she could to everyone, and she lost many friends herself at this time.
I do understand what you mean though OP. Another example- I was fostered for a short time in my childhood and really resented the foster carers attitude- they wanted to do their 'good human being and community members' duty iyswim. It felt like my brother and I were props in their life, helping them be 'nice people', they were helping us to make themselves feel great.
They were really lovely people, but I still resented their motives. Unfairly...