Sometimes people are just greedy.

It's hard to work out which coins will ultimately be successful.

Sure it is. But it is a bit different here though, isn't it? Considering that they have cashed out in fear, while still expecting the community that they dumped on to support them with the same token.

Communities can turn toxic, unexpected events like Justin Sun can happen, so people cash out regularly just so they don't end up as bagholders.

Many cashed out well before this. Cashing out regularly shows a lack of belief and commitment in my opinion, especially if there is no reciprocity back to the community that supported them. It is a hard position to be in if complaining about not getting support, while never haven given any support.