If you want to try it, just do it. People who jabber on about consent tend to be miserable humans. They focus so much energy on gaining unearned moral superiority because that gives them a sense of purpose.
If you do it and they tell you to stop, then stop. If they like it, continue. This isn't rocket science.
First of all, saying if they tell you to stop, you should stop, IS caring about consent.
But putting that aside, this take is like second-hand embarrassing.
You obviously have no way of knowing who is miserable and who isn't - that's something you're projecting onto people.
Which begs the question - why are you projecting this unjustified negative emotional state onto them? I would guess, based on the context, that you're probably embarrassed by your desires and afraid to talk about them with a potential partner - that's pretty common in our community and it's the problem the OP is having, which is what I think triggered you.
So when people suggest that it would be the right thing to do, you decide that they're trying to morally high-road you and you feel like you have to diminish them, in order to not feel like you've been accused of being bad.
And I notice you conveniently ignored the part where he suggested misleading his friend about why he's doing it, because it doesn't fit your pre-existing narrative that trying to actually communicate with someone about what you want is a waste of time and/or a fake moral stance.
Here's the reality - people say what they believe. It's not an attempt to claim the moral high ground. It's just what they feel is the right thing to do in a given situation. And frankly, asking for consent/being clear about what you want is hardly some kind of controversial viewpoint where you could justify being suspicious about people's motivation for suggesting it - it's pretty much the standard for decent behavior between two people.
What's questionable is when someone doesn't want to do that - when they want to engage in some kind of fetish activity with another person, but specifically do not want to tell the other person that that's what's going on.
Or when someone angrily defends another person's right to do that and attacks anyone who disagrees.