Controversial isn’t necessarily a bad thing. Plus, you obviously don’t know what his halakhic ideas are. Don’t go by what you read on Eidensohn’s blog without investigating for yourself.
And from where do you get that we are supposed to brush off gerim? The brush off 3 times minhag is not decided k’halakha in any sefer I’ve seen. Yevamos 47 says that we warn them about the hardships of being Jewish due to anti-semitism and if they’re still interested after this, than we bring them close; the Rambam (Issure Biah 13-14) and the Shulchan Aruch, YD 268, both pasken like this.
And in cases where a person has previous Jewish identity, either as a member of a non-halakhic movement, or someone with a Jewish father, we are duty-bound to bring them close, as it is obvious that such persons already see themselves as Jewish.