We are not asking: it can be completely appropriate.
To clarify, when I say “two piece bathing suit,” I am referring to a bikini. Are we on the same page here, as far as it regards definitions?
If we are on the same page, then I shall take the liberty to make the same kind of blanket assertion that you have: It is completely inappropriate, and there should be no debate with regard to this.
1. You know very well that we are called to be a holy and peculiar people, separate from the world; to be chaste, pure, and modest in the sight of God and man.
2. You know very well that the Reformers and Puritans would practically disown you for saying such a thing is acceptable in any public circumstance.
3. You know very well that if I were to post an image of a woman wearing that type of clothing on this forum, the moderators would severely reprimand me for doing so. And what, may I ask, would be their reasoning for doing so? More than likely, “That was an absolutely inappropriate thing to post here.”
I, for one, would not even consider a young lady to be an eligible person to pursue marriage with were I to see her wearing so little clothing.
The OP asked whether modesty requires full arm and leg coverage.
I do not believe that it does, nor have I advocated for that position.
All have varying degrees and ideas of what "modesty" really means.
This sounds like pure, unfiltered liberalism. “Modesty really means what it means to you.”
For some of us, it boils down to attitude and intent more than to covered acreage, with coverage only being one moving part in the whole equation.
This is a fair position, so long as “covered acreage” exceeds 10% of one’s skin.
Those of us who will not set blanket prohibitions on types of clothing for different purposes are also unwilling to accuse women of violating the seventh commandment because they allowed.....what? an inch of leg too much? a shoulder, a (gasp!) navel to be seen? Who decided that two inches above the knee was fine but three was adultery? You?
The WSC you cited is not wrong, but it's quite the onus to put on women that their duty to the preservation of the chastity of others requires they essentially wear a refrigerator box with armholes, and then cover those arms. There's a huge difference to wearing comfortable, context-appropriate clothing, and being wantonly immodest to the destruction of others.
1. You have skillfully dismantled the strawman that you set up in the first paragraph, and frankly, I agree with you on that point.
2. I never said that it was solely on the women to preserve the chastity of others. Far from it. I merely suggested that it was the duty of
Christian women to wear clothing that would not be a stumblingblock to their brothers in Christ. I is equally the duty of men to diligently keep their heart from violating the seventh commandment, however, this does not negate the responsibility of the women to wear modest and chaste apparel, rather than sensual and wicked apparel.
3. Your last sentence leads me to believe that you are not, in fact, advocating that bikinis are appropriate for Christian women to wear. If you are advocating for that position, I fear to lay eyes on what you consider to be “wantonly immodest.”