but I'm not quite sure what the point of "对此" is. I know it means "towards this" but I don't know why it's used here.
'此(this)' short for '此事(this affair)'. It is the pronoun for the topic that's preceded the sentence itself.
[topic]: "老师们正在威胁罢工" - "teachers are threatening to strike"
[comment]: "你觉得对此该做什么?" - what you think should be done toward (about) it?"
此(事) is the pronoun for this (affair) : teachers are threatening to strike
[topic]+[comment] is a common sentence structure, if you don't use the pronoun for the topic, you would end up with sentence like this:
- In this case, you can just omit the topic and make "你觉得对老师们正在威胁罢工该做什么?" a complete sentence on its own
It is just common sense to not repeat the topic in the comment.