It’s also possible this is misdirection purposely leaked by the Whitehouse. The purpose perhaps being to put Russia, and more importantly Iran on notice that the POTUS will not tolerate a counterattack on our forces in Syria.
Thoughtful points, but I think doubtful - as the whole point was to stop the spread and use of chemical weapons by the Russians (and others) used in Syria and the UK.
Assad didn’t just say ‘oh well lets gas them and make every body mad at me’. He had to clear it with the Russians and very possibly the Iranians al Qods troops under Major General Q. Soleimani’s command.
Germany is shipping chemical weapon components to Iran which are then shipped to Syria keeping Assad supplied. So that was the message to all concerned - we will obliterate your chemical weapons factories and stocks.
DJT was just asking for a more forceful alternative which would have escalated right off the bat. Perhaps, if the weapons are used again, then a stronger ‘worded’ message may be sent.