Yes it's a personal thing, but it has also been a matter of fashion, and still is. For myself I'd like to think that I can control it and use it in the same way a singer does. Anyone remember Maria Muldaur? Wonderful sultry voice but the thing that she had going (that was different) was a vibrato that matched the tempo. Great control and made all the difference. I'd like to be able to consciously use vibrato the same way, but that takes concentration and there's a lot of other stuff going on.
For most of us it's a matter of habits (good or bad). I was taught to play strictly with vibrato, so it's taken a while to be able to turn it off. Personal opinion: I've heard people here with awful vibrato that would benefit from turning it down and gaining control. I've also heard people who have no vibrato who sound dead and need to warm and liven up their sound.
It's a tool that can be used appropriately or misused. I don't think that there are any strict rules that one could apply, but I also think it’s best when used in a way where it's part of the communication of the music being played and not necessarily noticed.
The same is true for lots of other devices we use in playing e.g. growls, slurs/slides, false notes, altissimo, etc. Each of these is best heard as part of the context and communication of the music and not as a stand out gimmicks that distract. I think the majority can hear when any of these, including vibrato is overdone.
Does/should the majority rule? No! Each individual can do whatever they want and play for the rest of their lives in a closet just to amuse themselves. However if one has the goal of playing for others as an entertainer, then it may be a good idea to have some idea of how your playing is perceived by those you seek to entertain. Once again this can be a matter of fashion and changes over time. I don’t think anyone should feel that they have to follow fashion and hopefully there will always be individuals who are “form breakers” that change fashion or perceptions. This is where honesty and self awareness needs to come to the fore. If you’re “different” and not communicating well or achieving your goals as a player do you “stick to your guns” with an attitude of “I’m great and nobody understands me” or examine your priorities to see what’s most important to you? On the other hand there are real talented individuals who occasionally come along and tweak the way we hear. They are rare, but have in common that lots of people get where they are coming from...their artistry communicates.