You're arguing the point that because his help wasn't needed in the end that he shouldn't have offered to help.
But it's conceivable that his expertise could have been useful.
Did any other organisations offer subterranean expertise? Genuine question, e.g. mining companies, drilling, or was it just that Musk made the most noise about it?
My impression was that this was not a good-faith effort to help but rather to be seen to be helping, without any concern for whether his efforts were useful.
Which is itself a bad faith evaluation. I'd prefer to be kinder and thus keep the door open for other such "help" in the future. Fundamentally, he didn't do any harm.
Actually, I believe that other people were exploring the options of drilling a rescue tunnel from the surface. IIRC, there was even the beginning of projects to make a usable tunnel launch site for such a rescue tunnel.