Well, our unwillingness to be beholden to sponsors is just part of the reason we avoid advertising, but it's not an empty concern. We've done stories that big brands wouldn't like (the true story of Colonel Sanders, the New Coke debacle, etc) and we frequently share some unflattering stories in our Curated Links section.
The larger reason is just that I personally despise ads. I take great measures to eliminate them from my life--paying for YouTube Premium, using the SponsorBlock plugin, running aggressive ad blockers on every device, piHole, etc. It would be quite hypocritical for me to add ads to my own content, I don't think I could live with myself.
I know that some podcast providers wrap ads around everything anyway, but that's between the listener and their provider, there are absolutely ad-free alternatives.