The Brit constitution is whatever Parliament says it is.
Our Constitution is one of (supposedly) defined powers.
So, I’ll take the 1787 Federal Convention position regarding what evolved afterward as the 1st Amendment.
Since the draft Constitution did not empower the proposed government to restrict speech, press, assembly, exercise of religion, petition, our Framers recognized it was dangerous to itemize them. Why?
The 1A implies our rights are limited to those it itemized.