Partly you are right mkuu, partly you are not
Liverpool is Man Utd fiercest rival. This is the order, Liverpool, City, Leeds, Chelsea, Arsenal (according to polls/research)
Man Utd and Liverpool are very close in terms of success, in terms of trophies won, that is different with Man City, that's why even Sir Alex once regard City as just noisy neighbour
It would be 19th times, just one less, should Liverpool become champion yesterday. City was crowned 7th times. United is 20 times champion, who do you think threaten more their record?
Then I agree with you that, for United fan it hurt to chearing City to win title but you can't compare it with Liverpool
It is very true that now, we are in shameful state, we hope it is temporary
But Liverpool are in tricky situation, you are on high, but you don't win trophies..... That is much bigger problem, because you should take your chance when you have the opportunity. Remember not all all years will be rosy, this was your time..... But you fail to do what should be done