Nowadays there are many large platforms that block crypto advertising. It's not clear on what grounds they are doing this and what are their plans for a crypto market. There is evena version that digital giants are preparing some blockchain project and want to enter the market on better terms by holding it's development.
as you can see on the rule it is very clear on why they are doing this. and this is because they want to make sure the website is free of spam messages and also content that is misleading or scam project promotion which can lead them to trouble. if you read medium post about bounty well you will understand many articles are full of irrelevant and similar posts which is being targeted to drive traffic to token sales website. you know also that many ICO which have turn out to be scam (e.g denaro, Sym) are being paraded by bounty hunters on medium as good project to invest into.