Yes, you are over-reacting. I too have trashed Vidro, as well as Bowden for giving him the extension, but I have accepted it was the best option.
Yes he is a hideously un-clutch pop-up machine right now, and a boneheaded baserunner, but he has been hampered by nagging injuries which will likely heal over the offseason. Remember the anticipation when Vidro was going to come off the DL and make the 50-31 Nats an offensive force? He is a career .300 hitter good for ~18HR and ~75RBI in a full reasonably healthy season and a serviceable fielder. It is too early to give up on him, based on his career and relatively young age.
If he was let go, who plays second everyday in '06? Spivey? Carroll? I don't see any better free agents out there.