Who knows if it’s all a deliberate attempt at diversion? It would certainly be in character for any leader of an authority hierarchy to divert like this. It would particularly be in character for a sociopathic narcissist like Trump to do so. On the other hand, it does really seem likely that Assad did use chemical weapons again, and the UK and France (neither of whose leaders have much love for Trump) did cooperate with Trump in the attacks.
It’s mostly for show. It’s almost impossible to achieve anything by air strikes alone. I seriously doubt there’s any will to go in on the ground in a serious way. Even if there was, there would be huge ethical concerns about doing so, and huge lack-of-trust concerns about just who is doing the intervening.
Trump said some tough things about Russia tonight. That doesn’t matter so much as many might think it does. Talk, as they say, is cheap. If it’s limited to talk, and there is continued appeasement of Putin behind the scenes, it’s obvious that the talk was meaningless. Remember, the last time that Trump bombed Syria, he called Putin first so that Russia could get their men and materiel out of harm’s way before the bombs fell. Also, the expulsion of Russian diplomats after the chemical attack in the UK is less meaningful than it appears, because Russia is free to simply replace them.
Any rhetoric about “brutal tyrants and murderous dictators” is basically meaningless coming from a guy that pals around with the likes of Putin and Duterte.