In my own opinion who destroying bitcoin is those who doesnt like bitcoin and those scammers. And, ofcourse those competitors of bitcoin that wants to get rid of, wants to be on top or leading in cryptocurrency.
And the other people who will destroying bitcoin are the users of bitcoin that use bitcoin for something illegal are like (money laundering, support for terrorists and other) the illegal activities will makes bitcoin bad images on the peoples who don't know anything about bitcoin and the peoples will be scary hear about bitcoin without learning what is the bitcoin.
Though this problem can be solved or minimized by the means of the regulation released by the government in order to put order especially to those opportunistic people taking advantage to those unfortunate people. With the support of the government, the trust and the popularity of Bitcoin will rise up. Though the government will put taxes on top of it and would try to control it. Also all the currencies or anything can be used either in a good way or bad way that lies on the hands of the person or people's intention, motives, and its character.