Sure they can. Why not? Tons of Patreon supported people ALSO have tons of paid commercials on their podcasts or streams. Tons of open source based companies charge tons of money for support and for services. Heard of IBM / Redhat? Open source companies may also CHARGE for software. I mean, you may not approve (and I agree it’s incongruous and the upselling is sketchy) but it’s hardly a *binary" thing. Hell even PBS has blatant ads now in addition to fundraising and pledge drives.
I prefer CamNePlusUltra and/or CamDoublePlusGood.