Oftentimes, amendments like those are proposed because they will kill the bill. If AOC wanted the bill to pass and knew that it could not pass with that amendment, then she would need to vote against the amendment even if she otherwise agrees with the content. That fact is another reason that amendments like this are suggested: they force a politician to vote against something that they otherwise support.
So when evaluating her vote in the amendment, you need to consider the broader context of the bill that was being voted on to understand what her vote means. Was the bill as a whole worthwhile, or should she have tanked it for ideological means?
Oftentimes, amendments like those are proposed because they will kill the bill. If AOC wanted the bill to pass and knew that it could not pass with that amendment, then she would need to vote against the amendment even if she otherwise agrees with the content. That fact is another reason that amendments like this are suggested: they force a politician to vote against something that they otherwise support.
So when evaluating her vote in the amendment, you need to consider the broader context of the bill that was being voted on to understand what her vote means. Was the bill as a whole worthwhile, or should she have tanked it for ideological means?