Fine then.
KISS is not metal. At all. Of course, they may have inspired certain bands, but last time I checked, the black metal band Taake was influenced by the band "A-ha" (my user name is not a reference to that band btw). So I don't think influencing other bands, as you guys were talking about, has shit to do with it.
And KISS is just simple, repetitive rock with boring pentatonic guitar solos. You could probably say that about Black Sabbath as well, but Black Sabbath started the whole fucking idea of metal.
As for Priest, well, they are/were commercial, as you guys say, but there is no doubt that they are "metal" (and an excellent band). Judas Priest is one of the pioneers of heavy metal, so... I don't understand how they could NOT be metal.
Plus, albums like Screaming for Vengeance and Defenders of the Faith are some of the best heavy metal albums ever.
Judas Priest has a more metal element with the solos, drumming (later on, from Painkiller), the vocals, and some of the lyrics.