I dunno mate. I remember us singing “are you watching Manchester” on Wednesday nights in Europe, when we were the “one team in Europe”. I even recall the blues joining in when we both appeared at Wembley together - mid 80s.
I think the main difference is we tended to do that in a rather benign, piss-taking kind of way, but their vitriol has always been very bitter and filled with hate. Even in more recent years we might have sung ''Fergie's right, your fans are shite'' but they will come back with The S*n/Hillsborough references. Everton have gone the same way. We take piss-taking banners with anniversary cakes on to Goodison, they respond with Hillsborough gestures and Manc songs.
I remember singing ''are you watching...'' but pretty much every club had an ''are you watching ...'' song back then aimed at their biggest and/or local rivals.
United's stuff has always been ugly, and the envy, jealousy and hatred in the 70s and 80s from them was a disgrace, and it's something they've never shaken off since. Despite the Ferguson era, they've remained deeply obsessed with all things Liverpool.
To me, United have barely ever been truly relevant. They are a big club, of course, but when I started going to games in 1971 (ironically against United) then through the 70s and 80s United were simply a laughing stock. One that was insanely jealous of Liverpool and who believed (because they are entitled arses a lot of the time) that Liverpool had the success ''they should have had''. I put that in quotation marks because I heard that from them on more than a few occasions. We had what they believed should have been theirs. The reality was that they were shite and living in the past.
Ferguson came along and finally got it right, just as they were about to sack him, but their fanbase never seemed to get over their jealousy, envy and bitterness. To this day, despite the greatest period of success in their history, they remain obsessed with Liverpool the city and Liverpool the club. With Ferguson, they became more relevant to me in a football sense, and it was a shame that their rise coincided with our self-induced vacation from our perch, because we never really got to go head-to-head as two giants at their peak. Now Ferguson has gone, United have reverted back to being the United I always knew. A big club, but barely relevant to me in the scheme of things. One thing is for sure; I certainly wouldn't be arsed singing about them unless we are playing them, and even then it would be pretty benign piss-taking rather that hateful bile. To spout that kind of stuff their way I'd have to actually be invested in them and give a crap. I'm not, and I don't, so who cares? They still sing about us wherever they go because we matter to them and we are always in their heads. It doesn't matter whether we are great or shite now. We live inside their heads. The proof being that they never shut up about us.