With the libs in my life, the reaction to Trump being shot at has been "It's a shame they missed."
They have been hearing that Trump is a threat to democracy for the last 8 years, so hearing the so-called opposition to Trump suddenly support him has made them go "Huh?" and you can tell they're getting frustrated with them.
Now would be a good time to remind the anti-Trump people in your life that the Dems/Labour clearly won't protect them from Trump and fascism, and that an alternative exists.
The status quo is losing it's appeal. The important thing is to make sure people don't fall into the nihilist trend of "Both sides suck, there is nothing we can do. The world is terrible." A better way does exist and it will win. 
People need guidance right now and communism can provide that.