I am aware the law changed, now; admittedly I didn't until reading other replies to my OP. And I am not familiar with the nuance. We certainly have defamation laws in the US as well, so there's that.

I think criminalizing (or even "tortifying") lies is completely unworkable. This kind of edifice has to be full of exceptions to avoid immediately collapsing under its own weight. In the average political campaign (US or UK), how many lies are told that cause harm to a candidate's reputation or future employment prospects? One a day, conservatively.

The real linchpin is whether these laws are used in practice to protect the powerful from criticism, or normal people from vindictive harassment as you suggest in your example.

If your example actually happened, I think that first, people would ask the person claiming "XAA RAPES CHILDREN" for evidence. If the claimant failed to provide it, listeners would rightly view them as crazy. In any case, it is unlikely I could afford to prosecute it, especially if it caused me harm to the extent of causing me to lose my job or something.

Like everything in law, it's complicated and has pros and cons. My personal bias is to lean towards free speech if individual cases are in doubt.