Not true, music thru tube amps sounds very good too.
That gets down to one of the core philosophical differences between 'golden ears' and people that understand electronics. One sage engineer once said the 'perfect' amplifier would be a "short piece of wire with gain". What he meant of course was the true purpose of pre-amps and amplifiers is to faithfully reproduce the signals from the source of the music, adding and taking away nothing that isn't in the original program material.
So when one says they hear and prefer the sound of a tube amp over a solid state amp (with better specification by far) they are saying they like the modification the tube amp makes to the original sound. That's fine as it goes, everyone is entitled to their preferences, as long as you understand what is the cause of why you like it better, it's because the equipment is modifying the signals rather then just amplifying them. Certainly the original artist and recording engineer didn't feel the need to add that specific 'improvement' into the original program material.
So I'll continue to wish my audio electronics to be as accurate as possible to the original program material, rather then to add it's particular flavor to the music I listen to. Tube amps do sound different (that tube sound!), but there are specific electronic reasons for that, it's not magic. Speakers and room acoustics are the biggest variables in accurate audio reproduction as there one leaves the world of pure electronics and into the less perfect world of the electromechanical and audio reflections.
But then again there is a reason most pre/amps come with tone controls also, so you can modify the sound.