Is it ethical to contribute to a workshop one is organizing?
I've helped organize several minisymposia (MS) at conferences that are built entirely out of them, and it's basically expected that we submit to our own MS. Out of three MS organizers and 8-10 expected speaking slots, 2-3 will be from the organizers. A few workshops I've attended at more prestigious conferences have been similar. The conference wants its events to be full, and if the subevents are peer reviewed, especially double-blind, then there's no possible conflict of interest in my view. Even for single-blind review or no review (abstract-only submission) as long as you don't review your own work, there's no problem and self-submission is practically expected in the fields I publish in.