I feel we could just apply the same rules that led to A/B/O being barred -that if such topics are allowed they'll take over the whole meme, because everyone will want their light-Avenger OTP with a Trash Party twist, and they're perfectly within the bounds of other kinkmemes.

The issue in that case would be deciding a cut-off point, and I'd suggest it'd be a matter of whether the focus was on Character's abuse by Hydra or on Character's situation without Hydra. There have been some very good fills that are skirting the line wherever we choose to draw it, so I think any changes resulting from this debate shouldn't be retroactive, but rather to keep the meme on topic in the future.