I was a practicing Mahayana Buddhist for many years and I can assure you it is a religion. There is an entire pantheon with Buddhas, Bodhisattvas, ancestors are worshipped. There are temples, rituals, idols, altars, prostration, chanting, incense lighting, religious texts, etc. There is an afterlife via rebirth which you are trying to end via merit making (virtuous acts). Most of the religious practices are there. There is even a religious rite similar to the Christian sacrament of confirmation called taking the precepts where you make certain religious commitments, and you are given a Buddhist name after time of religious study.

I think it is pure fantasy that people believe Buddhism is not a religion. I think some people want to convert Buddhism into just philosophy because they want to take out the interesting content and drop the baggage (rituals, worship, etc.). Many are leaving Christianity with the hope of finding a spiritual community without all of the negatives of religion. However without the baggage there is no meaning or purpose and people will fill in the blanks with their own culture and religious upbringing.

Buddhism can in practice be very religious. The life of your typical buddhist monk really doesn't look that different from the life of your typical christian monk, they just utter different prayers while lighting their candles. The Pali Cannon reads a lot like the new testament too