Popa: Not really. The Gemara and Rishonim already say that Geirim have a high rate of leaving. That’s not a failure of just Z’man Hazeh.
DH: He is pointing out that in many Chareidi communities there are people who mistreat Geirim. It only takes one person to ruin a welcome to the community for someone who probably is already nervous about fitting in. He might exaggerate how widespread it is, but the end result is the same for the Ger trying to fit in.