Everything is a matter of conscience, isn’t it?
Nobody can challenge my conscience and we infer that Paul was basically saying, live and let live, don’t ever challenge somebody whose conscience either won’t bend or whose conscience is remarkably pliable.
But appeal to conscience is not a ground to never be challenged. Your conscience may not bend – and it would be wrong for you to go against it – but that doesn’t stop another from showing you from scripture why perhaps your conscience is more rigid on this matter than it needs to be. Likewise, your conscience might be pretty soft and flexible, but that doesn’t stop another from showing you from scripture why perhaps you ought to be a little more rigid on that matter. The fact is, our conscience is not a means of stopping other people from following theirs and to use it as a powerplay to get what we want is to abuse it.