Actually I think it is a great idea and it works for the UK because the
UK is small country or a large island - this form of free speech brings
things which are important to large numbers of people to the fore front
and a debate is a debate, not a decision - which are made later following
due process. It is open to anyone to start a petition on any aspect,
even Christians.
Would it work in the US - I dunno, possibly not due to the size of the
USA.
Anyway way this might help a bit.
You will see from the second link that as well as a "ban Trump" petition
there is also a "don't ban trump" petition - both by default were considered
together as they were "different sides of the same coin". However media
being what it is. The "ban trump" side was given more emphasis and the
media forgot to give the background and explain the e-petition system.
So what everyone got was the headline UK SEEKS TO BAN TRUMP
alarmist over exergerated story line - on both sides of the pond I might
add as the UK media are no better.
Personally I haven't a clue about US politics or what Trumps stands for.
E-Petitions and the Backbench Business Committee - UK Parliament
https://petition.parliament.uk/petitions?state=debated