I think these gov.uk petitions are really quite lovely and sweet; giving people the opportunity to feel like they have done something in a most cost-effective way.
They require so little effort to express an opinion too, no need to go out and march, protest or knock on doors either - just think of the stories one can tell their grandchildren - not I went to Greenham Common, marched against facism or rioted against the poll tax but I swiped a few pages and filled in an online form on my smartphone and got really activist when I shared a link on Facebook.
If it makes you feel good, then sign away.