Usually I agree with your calls on things being unsubstantive, but this one kinda seems fine? I don't think it's flame bait, just emotive language? And the substantive point being made is that online gambling should be illegal.

(apologies if arguing about mod decisions is frowned upon, I didn't see anything in the rules about it)

If it were just the one comment I wouldn't have said anything; the issue is the pattern (note the word "repeatedly").