Harmful? Hardly.
I don't suggest that his conclusions are all correct, or that his research was without flaws, but that does not mean that it is harmful.
Despite the best efforts of those who like to rewrite history to fit their modern agenda, and peddle it as fact to the unaware, the unread or the willingly ignorant via dubious internet "news sources," Kinsey's work is no more harmful than any other biology or sociology text.
I'm so weary of people for whom any mention of sexuality is immediate cause for the vapors.