The sound without the words would still be music. The words without the sound would be poetry. Not music. So first of all, yes, lyrics are secondary. If you are producing poetry, with a musical accompaniment, then the words are most important and the accompaniment is secondary. This is just basic terms.
Furthermore, the purpose of music is to please the ear. That's why it developed as an art form. Human beings do things because they please them, ease pain or otherwise satisfy urges. The urge to learn, the rush of adrenaline, the urge to fuel to the body or procreate, etc. So basically all widespread patterns of human activity will emerge BECAUSE they serve a specific purpose to humans. In the case of music, it developed and became widespread because the sounds are pleasing to hear. Period.
You can put together some other random mishmash of noise and CALL it a song, but if it doesn't serve the purpose that music serves, you're not actually doing anything and won't accomplish much (by and large people won't buy it or spread it or applaud it etc etc., and the few who do will usually be doing it as an attempt to gain respect or social status by claiming to like it, this has been proven by those prank shows where they purposefully make bad or random art and get a small number of critics to claim it's great)...in the same way that you can start driving a car and SAY you're in a race, but if you're not actually competing with someone else to reach a point before they do, you're not actually doing it.
This a clear and logical explanation of what music is, and can actually, if you pay attention, be extended to art as a whole. Thus, maybe you can understand why calling a piece of music "pop" is an invalid criticism. People liking something, in and of itself, is not a testament to it being bad. What you're probably seeking to say is that it's unoriginal or cliched...but I'll stop there.
Re-read what I said in post 41 and post 69. More than a decade after the fact, Wonderwall was voted the best and second-best British song of all-time by separate polls. You can claim it's mediocre or trash but you have no basis...and I can say it's absolutely brilliant and have more to back that up.