If I understand correctly, around 10 million USD per year (according to https://www.mpegla.com/wp-content/uploads/avcweb.pdf that's the cap, and from what I've heard Cisco is selling enough actual products to hit that cap, so providing their software for free to everyone else doesn't cost them any extra in licensing fees, just hosting and such)

That is such a nice service. Benefits everyone and near-zero cost for them.

Why is Cisco being nice about it? (Besides why not?)

I don't recall the specific timing of the release, so this might not line up, and I have no inside knowledge, just public information.

Cisco has some products which use compressed video in a browser setting. It would be useful if all browsers supported a good codec. Individually downloaded codec plugins suck, because installing is iffy. Therefore, give something away which doesn't cost licensing money to make your existing licensed products more usable.

And get some good feels on the interwebs.

Because several years ago, there was a fight over mandatory to implement video codecs in WebRTC. It was VP8 vs H.264. The biggest thing VP8 had going for it was no royalty payments. Cisco wanted H.264 because all of their devices supported H.264 and none supported VP8 and they already paid the royalties. So Jonathan Rosenberg, then CTO of the division of Cisco that managed this part of the business arranged to have Cisco cover the royalty payments for anyone implementing the WebRTC standards.

That wasn't enough, and WebRTC requires both VP8 and H.264 as MTI codecs.

Because it forces their competitors (in the video conferencing business) to take similar costs.