Eddie, most people don’t string their guitars with just three strings, which if you have loads of guitars l, I suppose you could do that instead of using a capo.
Using a capo is absolutely as musical and important to learn how to play pop and rock tunes authentically to their orignal sound as is learning the fretboard.
To say that capos should not be used is just being pedantic.
As for saying that capoing pulls strings sharp is only true if you don’t know how to capo correctly by assuming that the capo should press down only on the strings and/or action that is too high and/or the capo pushes too hard. Since giving examples is not allowed in the discussion, I can say that I can tell what voicing a guitarist is using and using a capo. So many songs use the open G C2 Dsus4 Em where the guitarist is holding the DG down with fingers 3 and 4 on the 3rd fret, except not in G, in other keys There are not enough fingers to make those voicings with even the most skilled barre technique. Capo it is.
So forget famous use of capos if that doesn’t stand as evidence, let the ear lead you to the truth.