Why did Michelangelo paint naked people?

Answer 1

The Humanism of form was a major focus for many artisans of the period, and it was common to include detailed anatomy (including musculature and facial structure) to art as a measure of its quality at the time.

Essentially, it was the style of the era.

Nudity as a vice is largely a creation of Western culture and truly only began around 500 years ago. It's a cultural nuance that is largely limited to Christian cultures, and even then only relatively recently.

There were movements from these same regions many centuries ago to censor some works of art, and as a result many famous statues or paintings were covered or re-worked to disguise or hide genitals in much of Europe's older art, but most works of this nature have since been restored to their original form.

Answer 2

If you mean the Crucifixion of St Peter, which is in the Vatican, it was commissioned by Pope Paul III.

Answer 3

Because the pope commissioned him to.