I think you have answered your own question.
No, of course it isn’t for most of us who identify as being female and actively pursue our femininity both physically and emotionally. For us – we don’t consider it crossdressing at all – we are wearing the clothes of the gender we identify with. The problem is that we have a masculinised body, and “society” doesn’t yet accept that we have an equal right to dress as GG’s do.
But …. There are some CD’s who dress purely as a lifestyle choice, and either don’t identify as being female, or don’t know it yet, or are in denial and reject it. So for them, yes, they will argue they are “just clothes.” Lets call them “vanilla CD’s.” But if they are going further and feminising themselves with makeup etc. then it might be more than a simple lifestyle choice, and they may have an underlying feminine identity. So they may tell themselves it’s “just clothes” – but is it? It’s getting complicated now, and my femme brain is hurting, so I’m going to stop.
I assume that drag artists are much the same as vanilla cd’s. Except that they also emulate women as part of their act – but they are (to most) still “just clothes”.