He may have semicha from Ner Yisroel but a better test would be to see if Ner Yisroel touts him as one of their musmachim.
There are plenty of people who call themselves musmachim of any number of yeshivos and have since strayed far from the ideals of the yeshivah were they originally achieved simcha. Yes it can be both ways.
What is really telling is a) that he identifies himself as a political activist b) one of his significant concerns is that these kids can’t speak ivrit and thus should cut back on limud gemarah. That hardly seems to coincide with the hashkafos of Ner Yisrael.
The description of the students he seems to be referring to also do not seem to be of the sort that pass through Ner Yisrael or Torah Vodayh or Mir or Chaim Berlin etc. vda”l.
Based on my own experiences and discussions I’ve had with many very experienced melamdim, his suggestions are off base.