Considering how easy it is to install the youtube ad blocker, I don't think monetizing a video is such a moral conundrum. As to why everyone is bugging you about it, I think that they're placing themselves in your position and are a bit frustrated at the money being squandered for seemingly little reason. People are used to ads. The vast majority of channels have them. They are easily blocked if you so desire and it's believed that about 50% of people do so. It's money being thrown directly into the trash for the sake of martyrdom. I say this to clarify the position, so it's a bit less baffling that people seem to be clamoring for ads.

I hope that helps.
thank you