I am arguing it because you continue to interject your opinion. Your unwillingness to argue is because you know you don't have anything that can change the debate to your favor.
Luke is superior to all of the Ancient Sith, you have consented this, so we need not debate about it. But the subject of Palpatine remains open. He is stronger than they are, not just because of a quote, but because he has exhibited a far deeper strength in the Force.
The Visual Guides confirm that he dedicated himself completely to studying the Dark Side. The dark side of the Force was so strong in him that it was decaying his body, and he was forced to drain the energy from Byss to sustain his evil. His clones, likewise, could not handle his intense power - which is why he regularly switched his essence.
It is quite clear. In raw power, Sidious is easily above all of the Ancient Sith.
If you disagree, that is your prerogative. But, until you can provide evidence that says likewise, the argument is in my favor.