@Brewster's Angle Grinder
You say "We should focus our energy on making sure it works well - e.g. it doesn't outlaw LGBT", but *how* exactly are you going to achieve that except on an individual, case-by-case basis?
How do you create a filter which outlaws "porn" without blocking access to sexual health sites or breast cancer sites or LGBT advice sites all of which "children" (defined as "anyone under 18") might have a legitimate reason for accessing?
The answer is, of course, you can't. All this proposal does is justify Nanny State censorship (which is an act of stunning hypocrisy from the Tories who criticised Labour for wanting to introduce Nanny State legislation!) and trying to justify it as "the lesser of two evils" is nonsense.
If you want to be protected from "evil" that's your business, don't treat everyone else like children because you can't trust yourself to act responsibly.
(PS and dragging in Gun Control is just a massive red herring, there should be a Godwin equivalent...)