I don't think you're going to be able to win this one, P.R.
Even if you subscribe to the idea that people THINK she's stronger because she doesn't hold back her physical power like Superman,
and thus that Kara is not "really" that way,
you're still conceding that the power she displays under normal circumstances is higher than what he displays under normal circumstances.
That's precisely WHY people thinks she's stronger by that particular theory, after all.
And Joe Kelly, Verheiden, and Mark Waid DID treat her as effectively stronger than her cousin, even as Loeb had before them.
The feats/comics support him being stronger more than they do her.
And no, Loeb made it almost blatantly clear that he believed Superman stronger. This is the same writer that in an interview said he believed that Superman was the world's most powerful hero.
It was made clear that Kara's lack of practice in control of her powers made her seem more powerful. It was a running theme, that was later disproven, especially when they came face to face.
If you want to argue that Superman holds back more than Kara, I'd agree with that. It doesn't make her stronger though.
There's the all-important consideration of time (which I, for today, am unfortunately out of), i.e. WHEN statements were made and events occurred. I remember Mark Waid making similar statements about Superman, before Jeph Loeb re-introduced a Supergirl FOR plausible use in the DCU. Once that happened, though, I could predict a lot of honor coming her way from Waid, which Legion and Brave and the Bold fans were happy to see her receive soon afterwards.
@abhi. So you just gonna ignore me asking you about the Xenith vs BRB scans bro? I see how it is. A little disagreement about one issue and a brotha gets ignored smh.