I've heard a lot of similar concerns from people who don't have much experience with VR. The general assumption is, that the display format is so immersive, that depictions of offensive content will somehow leave a greater impression than normal.
In my experience, this doesn't happen. I find the content equally disturbing (or not), regardless of whether it's on a phone, desktop or headset.
Isn't this epilepsy protection a counter point to this? I don't think an epileptic response is a risk of reading a blog post, and even watching a video online is a much smaller and more controllable example, and if pre-recorded it's probably straightforward to automatically detect.
In my experience, this doesn't happen. I find the content equally disturbing (or not), regardless of whether it's on a phone, desktop or headset.