They are also blocking sex education sites, sites that help victims of rape and domestic abuse, and a lot more.
Also note the mission creep. It was originally supposed to block #*$!, it is now also SUPPOSED to block file sharing sites, extremist (in whose opinion?) sites etc.
One the the government will probably just decide to block everything except big media sites and large e-commerce sites.
Also notice it requires website owners to contact every UK ISP that blocks then for review. It is going to mean a lot of foreign websites will simply not bother.