These can be valid points for some, and carry less weight for others (say, if you live in Paris and are offered a good job in London, and they help you deal with the visa stuff, for most it's probably also nice to be able to visit Paris much more easily than you could from NY or SF.)

At any rate, "not sure why anyone would prefer London with the post-EU laws" is very different from "they decided they don't want me because they're not in the EU (even though there might be an otherwise nicely sounding arrangement available for me)."