Your comment belongs higher. When given the opportunity to make money by social media advertising sometimes in the thousands or millions, companies, share holders, and conflict of interest groups take it. Cablemod’s burning adapters, cryptocurrency scams, payed positive youtube reviews are some great examples. In general there is no honor system and its best to assume anything that can be abused will.
Also manipulating votes is incredibly effective towards swaying public opinion due to the bandwagon effect. Spend a days worth of effort making fake accounts and downvoting any opinion you see as undesirable and most people will follow suit. This is especially bad in echo chambers like on twitter, reddit, etc.
I wish a broader audience could be aware of this. The best I can do is try to spread the word.