No, I don't think this can be said in general, especially not on electric guitar. On classical guitar, this is quite objectively the case for the G-string because it's a pretty thick monolithic nylon pillar at low tension, which can easily be pulled out of tune and has considerable inharmonicity. But for steel strings, this doesn't apply, except for very low strings – the low B string of a sevenstring guitar is definitely more prone to going out of tune, but I don't suppose that's what you're talking about here?
The reason I'd suspect why you perceive the b-string as going out of tune easier is the tuning system itself. The tones on guitars and keyboards are based on 12-edo temperament, which has in the 19th century been established as a decent approximation to the natural just intonation, which is what I would consider the definition of “properly in tune”. 12-edo works very well for fourths and fifths, so if you tune these with a (12-edo) electronic tuner, most pairs of strings will sound very well in tune since: E-A, A-d, d-g and b-e are all perfect fourths.
Not so the pair g-b: that's a major third, and the major thirds in 12-edo are actually quite significantly too wide. So in a sense, the b-string of a properly tuned guitar is always too sharp!
This isn't universal though, it depends on context. The b-string is too high in an open G-major chord, but not in an open E-major chord (here, it's the g♯ on the g-string that's too high). But the b-string is the only string where a major third occurs within a chord over a single fret, and many especially electric guitarists use such bar chords over a single fret quite a lot. Therefore, the b-string is perhaps where major thirds are most commonly voiced, leading to the impression of being most out of tune.
It doesn't help that both these bar chords and the other option (three fingers on the d-g-b strings on the same fret) tend to bend the b string up even further through pressure/space constraint, so the 3rd note is then even worse out of tune than it would be on a piano.
As a solution, you could try always tuning the b string a little flatter than the tuner suggests, about 10 ct. That's what many blues slide guitarists do, especially when tuning in open-G: then that all-in-one-fret chord is basically the only chord used. When not playing with a slide, this is unfortunately no good option because anything but major thirds that you play on the b-string would sound much to flat.
The only “proper solution” would be to get a guitar in 31-edo, which approximates fifths and thirds equally well. But such guitars are pretty intimidating...
Also, any keyboarder you want to play with would kill you.
