I only judge a pronunciation that doesn't match up with Tolkien's guidelines when the speaker is in a field that requires some attention to pronunciation.
I don't know how my reaction would be for a mispronunciation in, say, a lecture that's not about languages, but if it's an adaptation, say, or a musical performance...
Whenever you're performing something in a foreign language, the least you can do is respect said language enough to pronounce it right or as close to right as you can manage. Even if you don't say it that way in real life.
Now, what gets really interesting is when it appears that Tolkien does not follow his
own rules. What's one to do then?