Well, if you support Hamas after they butchered civilians, yes you'r supporting terrorism.
Second, the Israeli military has killed much, much more people, including thousands of civilians, kids and mothers over a half a century.
There are countless of videos and reports of rich settlers, harassing, stealing property and straight up killing regular palestinian farmers and families just living in their houses.
And third. Israel has actively supported Hamas to destroy moderate opposition like the PLO - the good old divide and conquer strategy.
So unless you also want to detain supporters of Israel this doesn't really make sense.
And no, you shouldn't detain them either like this.