The argument is that the "simpleness" of the doorbell isn't a good heuristic for the amount of impact.
According to wikipedia [1], the transformer on a standard doorbell can use 2-3 watts of power at all times. That's 1400-2100 watt hours per month — about one hundred times as much as a ring doorbell uses (Less than 20 Wh per month).
The cost and impact of the Ring includes more manufacturing, and I wouldn't be surprised if the Ring ended up having a larger environmental cost, but it's not as clear cut as your incredulity makes it seem.
According to wikipedia [1], the transformer on a standard doorbell can use 2-3 watts of power at all times. That's 1400-2100 watt hours per month — about one hundred times as much as a ring doorbell uses (Less than 20 Wh per month).
The cost and impact of the Ring includes more manufacturing, and I wouldn't be surprised if the Ring ended up having a larger environmental cost, but it's not as clear cut as your incredulity makes it seem.
[1] https://en.wikipedia.org/wiki/Doorbell