No they aren't.

This is an internet myth pushed by certain sci-fi writers doing incompetent research.

Disney were certainly in favour of the US's most recent copyright extension, but the main driver of it was the need for the US to move to a similar period to the EU for international treaty reasons.

The EU had moved to Life+70 years as a model because it unified to the longest period in the block when it unified the copyright period across the entire EU, under the logic that no copyright owner should have their term reduced as a result.

The longest period in Europe was Germany, and Germany's long copyright period was the result of lobbying from local German publishers, nothing to do with American companies.

It's really a bit of US exceptionalism to think Disney had much to do with it.

The parity excuse is always trotted out, but notice that nobody actually does parity. That US law doesn't deliver the same thing as the existing EU law, it just increases all the US limits with "parity" offered as justification.

That's on purpose to allow the same parties (if not called out by the public) to run to the EU to demand more "parity" increasing the EU limits too. Back and forth forever.

Regardless of whose fault it is, I think copyrights are too long. I think they were considerably more appropriate before the copyright extension act.

I'm not sure that this is correct. Spain used to be life+80 (a copyright term that dates back to 1879) and this got reduced to life+70 (but only for authors who die on or after late 1987, so this is a long way from affecting PD status) with EU-wide rules.