This wasn't a "W-'04" sticker or something, though -- 'Support the troops' is not a particularly political statement. I'll wager the state government already supports troops, not just in a "moral support" way but with actual money and facilities for their National Guard units, etc.
Our Democratic Gov. has made it a point to attend every funeral of every serviceman, service woman who dies in the service of this nation. (While respecting the family's wishes) I give him credit for that.
I work for a county in Oregon, and like the state, we are not allowed to use our time, publicly owned property, or publicly owned resources to make any political statement. That being said, supporting our troops is not a political statement. I agree with you on this.
It is funny (or not) that during the campaign (political) a blind eye was often turned towards liberals who emailed, faxed, proselytized, etc.. on the public dime.. but whoa be to the guy or gal who just wants to express some good ol' fashioned American patriotism!