A bad phrase to use online in any case. It so often sounds like a patronizing scold.

If you need to instruct people (and why do you if you aren't their parent or reacher?), it's kinder to say: "You need to ..." I can't tell you how many people I've muted for a title like, "10 Books You Should Read Before You Die." My reaction tends to be: Dude, I earn my living as a book critic. Don't tell me what I "should" read.