You could certainly claim that this is an obvious marketing ploy to get Trump to join, but as a near free speech absolutist, I can't help but applaud this giant thumb they just put to Twitter's nose.
Is Gab inviting retaliation?
They are WAY past that.
The knock against Gab is that they allow "hate speech." Here's the thing: The Constitution allows hate speech. You have an unalienable right to hate speech, love speech, benign speech, speech that advocates the placing of pineapple on a pizza even though everyone knows that's wrong.
Unpopular speech is why there is a First Amendment. You don't need to protect speech that is popular, you need to protect speech that is not.
"I disapprove of what you say, but I will defend to the death your right to say it"
There is an element of self-preservation in this. The more you try to suppress unpleasant speech, the more you get, and the more radical it becomes. Few things are more predictable than that.
There are limits, long codified in the law, for speech that directly facilitates violence. But you don't want to go down that road too far either, as there are many people far too ready to turn common metaphors, such as exhortations to "fight" into crimes when it serves their political purposes.
On Jan. 6, as lawmakers were certifying Democrat Joe Biden's victory, Republican Trump took to a stage near the White House and exhorted a crowd of supporters repeatedly to "fight" - using the word more than 20 times - and "not take it any longer."
There are many things on Trump's Twitter feed I disagree with, there are many things about Gab I find distasteful (that's why I'm here instead) but I support your right to read what he says, and Trump to say what he wants. If I don't like it, the solution is not less speech, it's more.
Speaking of which, stop putting pineapple on pizza.