BBC calling encryption "controversial privacy tech" is deeply disappointing and dangerous.
It's uncontroversial amongst people who value their privacy.
The tension between the two camps (there are obviously nuances and this is a false dichotomy) is at a current peak. It's an ongoing controversy. It's a matter of public debate.
You might have liked it better if the angle had been "...which the government, controversially, wants to clamp down on" or something.