Going to throw my $0.02 in here:
- Israel has banned several BDS and anti-Israeli 'activists' before, so I don't think this move is unprecedented.
- IMHO, I personally think that banning them isn't a good idea. I can't imagine that anything happens where allowing them into the country would materially change their position, and while yes, there is an opportunity for them to grandstand, there is also an opportunity for them to put their own feet in their own mouths which can then be used against them in future campaigns. I also think if Bibi invites them to meet with the knesset, or in the PM residence, and they refuse, they're the ones who look bad and not him.
- While the progressives running for President have made it clear that very few (if any) of them are friends of Israel, the Anti-BDS resolution that passed a few weeks ago received about 95% of the vote in congress (even Ayanna Pressley, who is part of the 'squad' broke with Tlaib and Omar and voted in favor of it). So while there is reason to believe that support for Israel is eroding, it's not gone yet.
- As others opine banning them enables Bibi to play to his base right before an election, and enables them to play to their base. If Bib wants to appeal to voters in play for the upcoming election, he *could* invite them, and expect them to deny the invite. For them - there is very little they could do in this situation that loses them credibility with their base, for bibi, allowing them in erodes his credibility with his base.