Fr. jenkins is overlooking the fact that sspxers are not validity freaks. So, they have more than just validity concerns as for why they attend TLM and trad chapels. Some are validity freaks, but most are not/should not. Validity doubtism and doubtism in general has already been mastered by the sspv/cspv, and most trads have actually rejected that mentality. So, I guess we shouldn't be surprised. Doubtism can be so blinding that one can come to think it is better or "ideal" not to go to the sspx, but if you do have to go, do not receive communion, and just pray your rosary. Because, a few "dominus vobiscums" are not sufficient. It is unfortunate times.
I will agree, that I would not be comfortable with a novus ordo priest officiating a marriage in an sspx chapel. But, that is not what I understand is happening. All the novus ordo priest is doing is basically standing there and witnessing the marriage. There are much much worse things in the world than that.