Certainly not excusing it, but Iran's proxies have been attacking our bases for over 15 years now. We made our point with Soleimani. They made theirs by showing they "could" have inflicted casualties had they intended to. For all we know we had Intel this was their plan and that's why we didn't try to intercept their missiles. It's probably still too early to tell so I'm just WAGing.
If we hold up here after this attack, it allows Trump to show the world and his domestic anti-war opponents that he's reasonable and truly doesn't want a war. It's an opportunity to just issue a statement and say that future attacks by Iran and their proxies will not be tolerated even if American forces don't sustain casualties. You lay out very clearly that if Iran does undertake anymore attacks or revenge, including terror attacks, proxy attacks, cyber, eytc that you will retaliate with overwhelming force.
You say we're are giving Iran a chance to show they're serious about descalation and come back to the negotiating table.
I really don't know that our readiness and force levels are currently at a high enough level to really get into a legitimate war with Iran right now. We'd need a WHOLE lot more time to build up men, material, and equipment.
Even though we have air superiority and superior technology, Iran has come a long way in the past 5-10 years. If they suddenly mobilized to hit all of our Middle East infrastructure and personnel, we'd take heavy losses and we'd need time to mount a response. There's no doubt that at this exact moment Iran has an overall advantage militarily over us because we have so few troops and resources in the area.
Even if you want to retaliate I think you take time to first build up your forces so that you can more easily deter any Iranian retaliation after your own. Right now we don't have the pieces in place to do that. I'm sure DoD and the Joint Chiefs have impressed this upon Trump and even he should understand it.