It's AZLyrics's responsibility to police their own trademarks, so it's okay, unless they say it is not in a C&D letter.
So it's legally okay, as far as we know.
Still a dick move, though. It's not okay in my opinion. But I'm not the one who may gain or lose thousands of dollars by deciding whether or not to do it, either. I can't say for certain whether it would be okay or not from outside my comfy judgment armchair.
It's blatant, intentional trademark infringement for direct commercial gain. IANAL, but I would think this might result in something quite a bit more expensive than a C&D -- like a lawsuit with punitive damages.
ETA: and now the site owner is on record here on HN stating that the intent was to steal search traffic. I'm sure this is a cutthroat business ... but this is an open invitation for one's own throat to be cut.
So it's legally okay, as far as we know.
Still a dick move, though. It's not okay in my opinion. But I'm not the one who may gain or lose thousands of dollars by deciding whether or not to do it, either. I can't say for certain whether it would be okay or not from outside my comfy judgment armchair.