Hinduism is a polytheist religion, but some Hindus want to deny that. Are they ashamed about their polytheism?

 

What a Muslim means by Polytheism maybe different by what a Hindu means by polytheism?
No practicing Hindu as far as I know carries any negative connotation to the word polytheism or pagan, unlike followers of Abrahamic religions.

Coming back to the main point Hinduism is Henotheistic. Now what is Henotheism?
Henotheism means that there is a central main deity and all other deities are forms of that God.

In Hinduism that central god is called Brahmann/ Parabrahm / Paramatma .
He is formless, massless and all pervading. He is said to have no birth or death. All other gods in Hinduism are said to be various manifestations of Brahmann. Brahmann is symbolized in writing by the syllable "Om" usually in Devangari script.