I understand where you're coming from but this poster is not saying "because I said so." It's implied in what she's saying that 'to God'...it's wrong. Personally I don't think the drift of the wording is the best. Lust over someone or the idea of someone you shouldn't be looking at in that light is wrong according to scriptures. That, which she'd probably agree with, is a report, not a message originating with her.
The approach is probably just going to have a negative effect because it'll sound like constricting people is the goal. When you leave off the 'why' of things and just harp on what (the 'this' or 'that' of what not to do), it's going to be taken that way. Controlling, not caring. If someone tells me I should bow towards Mecca because x,y,z...I may really disagree with them, but if their motivation in saying it is thinking it's good for me to observe, it won't cause me offense. They're not out to ruin my fun but (imo mistakenly) think I'm doing myself a disservice by not paying that homage. That's their driving motivation.
Judge not lest ye be judged doesn't mean you can't express recognition of morality according to God. It means don't be a hypocrite. To me it also eludes that if you do something AND are being a hypocrite in the process, there's more weight to that than if you did just did whatever it was. There's a difference between discriminating (in the sense of exercisingdiscrestion/sharing discrestion) and judgment. Judgement in the sense being spoken to means condemning (actually
casting stones, authorizing yourself to exact judgment, like the passage in John).
I don't think she's saying she's the judge. She could have simply quoted the bible along the lines of what she was saying (the drift would be a little different). . You likewise used discrestion in your response back to her, it just was developed (which helps).