I don't know. When Belichick wanted Rodney Harrison, he called him personally and invited him out. When he wanted Roosevelt Colvin he met him at a diner and pitched the Pats to him. If Belichick really wants you, he will meet you.
Word was even before Landty signed with the Jets that the Pats were scared off by his medicals. Maybe Belichick had already made up his mind to pass on Landry before Landry even came in to visit and the Pats kept the meeting as a courtesy (a report the Pats or any team canceled a visit because they didn't like a player's medicals would tank the player's free agency value). If that was the case, I can see why he wouldn't meet Landry.
I can see why Landry is upset, but I don't see it as a big deal. Landry wasn't a highly sought after free agent. Heck, if the Jets ended up getting Reggie Nelson, they might not have been as hot after Landry either. He was signed after a bunch of safeties were signed including Nelson, Meriweather (who the Jets were also reportedly interested in), and Stephen Gregory. He looks to be a good pick up after one game, but his injury history is a big question mark which was why he didn't get a big multiyear deal.