Personally, i think it sux that Bitcoin is used for this, but it's the same with guns, gotta take the good with the bad it's just a tool, as humans how we USE it is up to us! When i think about it i would never use a crypto at all, except maybe XMR or w.e, as using Bitcoin leaves a "money trail" you can't erase! lol
That's why i always think it's funny when they say Bitcoin is used for bad shit, ya cause criminals want a money trail, they use cash, it can be counterfeited and is untraceable mostly.
That is good reason, bitcoin is uncounterfeitable and it is also safer. fiat, gold, bitcoin and even property can be used for illegal transaction such as buying drugs.