Personally, I think that if you want a trigger warning in your own series, then great. If a creator chooses to do so, then that is fantastic, and I applaud them for their choices to risk immersion in exchange for happy viewers.
However, if a person chooses to not place trigger warnings within their videos, I don't think they should be chastised.
Trigger warnings in a horror series, in my opinion, are ungodly unnecessary. People should know what to expect when they are watching a series that falls into the genre. It is our job as (horror genre) creators to make people uncomfortable. If people are triggered, then we are doing our job correctly.
TLDR: Good job to those who choose to warn people, good job to those who don't. We shouldn't have to, people are dumb.