You don’t have to be a jerk about it. And after reading about this briefly I think that your presentation is misleading (and possibly factually incorrect; I didn’t immediately find sources that ISIS terrorists died from chemical exposure, though I didn’t look long).

Wikipedia says weapons there were being decommissioned, and The Guardian says when ISIS took the facility the US wasn’t particularly concerned because there was nothing usable or intact there.. We didn’t invade Iraq for decommissioning old weapons.

And it was not far-fetched that Hamas could have been using tunnels under hospitals as a command center. Most people just don’t think attacking the hospital on the surface is justified even if so, since the people on the surface had no way of avoiding it. But any excuse to ethnically cleanse Palestine will do for right-wing Israelis.