I'd say that CCTV is quite different to wiretapping. You (generally) wouldn't have the expectation of privacy in a public place, most people would expect that phone calls, messages, etc do remain private.
Now, GCHQ is no better than the NSA for that either, but I don't think CCTV is a good comparison.
While his leaks expose surveillance, he was useful idiot https://en.wikipedia.org/wiki/Useful_idiot in hands of Assange club. And it might be event of his saving was trigger for Putin to start war. So no, I'd better see whole camaraderie before court and sentenced. Regardless of 'heroism'.
And yes, most of modern supporters of Wikileaks / Assange / Snowden / etc, chanting 'release Assange' and 'pardon Snowden' are useful idiots in hands of tyrannies like BRICS club.