This is not true. You can in fact block specific channels. From YouTube support[1]:
> On certain pages, such as your Home and Watch Next pages, find a video from a channel that you don’t want recommended to you.
reply> Click More next to the video title.
> Select Don't recommend channel .
[1]: https://support.google.com/youtube/answer/6342839?hl=en
This is also not true and hasn't been so for years. One can set a preference to "not recommend", but one can not explicitly block any channel.
replyDepending on your particular "preference constellation's weights" (over which you have no direct control), you can, in fact, be shown videos from that channel again.
You can block from recommendations but there's either a fixed length with the oldest bumped off or it resets. I have to reblock stuff all the time.
replyAnd the community posts and polls from random communities you have no interest in and don’t give you the same “don’t show me content from this channel”
reply