Yes, it is a valid argument, because it's hypocritical for someone who is clearly not worried about their misuse of my language to get all in a huff over my misuse of theirs. There's also a huge discrepancy in the level of "bastardization" going on; "hentai" is a relatively rare word in English compared to how often Japanese use "mansion" for an apartment building, say "(something) getto!," or even go to a "viking" to have a buffet meal. And we will never come out with a cartoon about crossdressing and call it "Watashi Watashi Watashi no! Ichigo Tamago."

So as a professional linguist (of sorts), I declare this whole discussion stupid in the first place.