There is already an extension to SCTP to encapsulate it in UDP, it isn't in Linux but is in the FreeBSD reference implementation.
The userspace SCTP stack that gets built into Firefox for use by WebRTC will do it too.
The userspace SCTP stack that gets built into Firefox for use by WebRTC will do it too.
Similarly, once you have a userspace SCTP stack you have allowed the garbage to reach userspace resources.
Everyone knows how to not be a jerk while using UDP or SCTP, but people who have the goal of being a jerk are more manageable if you only give them remote SCTP access.
My home firewall is set up to allow anything originating here to pass but block most things from outside. For this to work the firewall needs to be able to track the state of the protocol exchange which will be different for each protocol. Few firewalls can do this for SCTP or DCCP yet, I'm in the process of adding SCTP support to the one that I use.
The point that seems to be getting lost is not that I want SCTP or DCCP support. Its that I don't think anyone should accept anything that could become a UDP arbitrary access loophole. The point of the current path is to replace the problem techs and add use cases safely as we go to gradually pay for a better network by making standards that aren't just the easiest thing for web-devs.
Every time someone tries to walk too close to the edge in a way that can open security problems for people who aren't running a server fully opted-in to web 2.0/etc, they risk a security backlash that could ban browser updates and effectively delay/kill unrelated innocent features and fixes with ripples for ~5-10 years.