I don't think it's Compulsion, just the fact Seanchan as a whole don't see much difference between male and female channelers, and Tuon, as a sul'dam, is particularly aware of the risk. The prospect of HUNDREDS of them organized and clustered around their own Power wrought fortress city is enough to scare the bejeezus out of any Seanchan. Add the supposed WMD Elayne unleashed by leaving a gateway partly unraveled, the sinister and palpable "Dark Ta'veren" force Tuon experienced meeting Rand AND the fact that sul'dams ability to channel isn't common knowledge (knowledge the bulk of Seanchan lacks Tuons incentive to rationalize) and Tuons attitude is quite understandable, if no more justified. The Wonder Girls have already decided their best long term defense against adam is to broadcast the fact sul'dam can channel, and if they suceed Tuon is likely in for a very different life than that of the Empress (may she live forever).