Sure. But it's not actually terrorism, is it? In fact, as worded, completely inoccuous activity seems to fall under the act - the definition of "UK-related activities" in the section includes literally any activity taking place in the UK. So intentionally helping set up a foreign embassy seems like it falls under the act.
Regardless, national security it may be, but terrorism it ain't.
You haven't explained at all - and still haven't - why you felt the need to accuse people of thinking it's OK. Remember you started with "well that's OK then" - implying the parent comment thought ICE was fine to shoot people - and then said "Do you think it’s ok he got shot?"
You have only explained that you think what ICE did was wrong. You haven't explained why you felt the need to imply that other people thought what ICE did was right. I guess you aren't going to.
Imagine if I replied to your comment with, "do you think it's OK that JFK got shot?" You'd be pretty confused, right, because you haven't said anything to suggest you thought it was. That's exactly what you did, just with someone else, not JFK. There was exactly the same amount of hint that the person above that it was OK.