That is an interesting perspective, but let's see why it is likely wrong. Obviously you know something about Oregon and Washington utilities. In Washington State most of the public is served by PUD's, cooperatives or municipals. In Oregon the vast majority of the public is served by Portland General Electric and/or PacifiCorp, with some being served by cooperatives, PUD's and cities. Oregon government has often sided against public power.
Historically, the WUTC has never been a friend of public power in the state of Washington. The publics are not under the WUTC's control and it has repeatedly tried to gain control over them and failed. But in this case the WUTC is opposed to refunds. The Oregon PUD is also opposed to refunds, so the public ownership issue differences in the two states must not be the common thread. It is likely something else.