[ He knows he doesn't have a leg to stand on with regards to recklessness. He knows that should he attempt to challenge that, Alucard will have a long litany of probably deserved accusations and that doesn't even count the deserved accusations that Strange knows himself but hasn't told anybody. He knows that he shouldn't fight this.

....but dammit, he really wants that book. So he changes tactics a little. ]

That book has magic in there that the world hasn't dreamed of. It's foolish to let such resources sit in a moldy old basement or wherever you keep your books.