Re: Politicize all teh thingz!
Depends how you look at the blackmail. Trump was elected based on assurances, he has been looking to get those funded, the Democrats were refusing to do so - I'd say they were as bad as each other.
Trump - for being unreasonable in his demands at the time.
Democrats - for consistently refusing to fund promises made during a campaign which they lost because the electorate wanted, in part Trumps plan.
It doesn't matter whether you agree with Trump, the man is a fool. But the bottom line is that a majority of US citizens who bothered to vote chose him based on, at least in part those border wall promises.