Bothsideism doesn't work here, because the one breaking norms are Republicans. You said we can trace it back further, yes, the conservative movement to ideologize the SC start as a backlash against the Warren Court for their progressive rulings.
There's no outrage here. If you follow this and the previous convo about pros and cons of filibusting Gorsuch, I was simply making the point that relying on the like of McConnell to suddenly abide by norms, hoping that they'd moderate their action is deluding yourself, and so did
@Ubik.
Which isn't to say that what you said about the function of the SC and the need to limit their legislative power isn't correct, but an acknowledgment of the fact that there's no mythical land where judicial neutrality exists and both parties can work together to appoint fair minded justice. As such, Democrats will simply have to do what's logical for them if they want to exert any influence over the direction of the country, court packing if needed.