I didn’t find it confusing.
I was never confused by that line.
I think you guys are underestimating how confused newcomers are to the series when that line is spoken. At this point in the franchise, we only know of one Skywalker: Luke. We haven’t even heard the name other than when referred to with Luke.
While I don’t like all the changes in the Special Editions, editing the line to, “The son of Anakin Skywalker must not become a Jedi” makes it so much easier to understand. The whole line should have been rewritten, frankly.
I see what you mean, but I never had trouble understanding what he meant when I was a newcomer——and I was just five years old when I first saw ESB!