I don't really understand how the whole "so he can play elsewhere but not for United?!" thing is somehow controversial. There are plenty of players and people who I don't wish to see associated with United for moral/ethical reasons. This doesn't mean I wish they'd all die or be sent to a gulag. How does this make me a hypocrite?
Because then your moral/ethical reasons are not actually moral/ethical, they're more convenient to self. Morals and ethics transcend club fandom.
If you felt Greenwood's presence at your club would be a blight to football, and be a detriment to progress on sexual assault (it's not but bear with me for a second), then why would you be ok with him starring for Liverpool, unless you'd derive pleasure in playing the moral champion card (we're so much better than them)?
If you want to be logically consistent, it's either you
1. Ignore all moral/ethical considerations (that's where I am)
2. Don't want him at United for selfish reasons (don't want the negative attention, losing the moral high ground, not wanting to have difficult conversations with your daughters or something) but don't mind another club taking the hit
3. Don't want him at United for moral/ethical reasons (he should not be a footballer, bad example for kids) in which case, you also don't want him playing football at any top level club, or profession that has people cheering for him. He's free to be a plumber though.
If you don't want him at United but wouldn't care about him at another club, and you're claiming morals/ethics, your morals are low-grade