Let's not forget that John Oliver are a comedian and a actor.... so their main goal is to find content that are controversial. Bitcoin and Crypto currencies are one of those topics that can be exploited to push a lot of buttons and get the most reaction from viewers.

These people thrive when they can pick people and technologies apart for their own gain. So yes, Bitcoin and Crypto currencies are a easy target for them and there are a lot of scams and shitcoins that are giving them a lot of content.