Is it inappropriate to write to a Judge requesting they preside at your hearing?

I wrote to a judge who previously presided in one of my cases. I felt since she knew the history of my grandson she would be fair opposed to a judge who knew nothing of what my grandson has been going through over the years. The reaction I got was I committed a crime in contacting the judge and my letter to her was filed with my new court case as if I was attempting to bribe her or her show predjudice in my case and will probably hurt my attempts to see my grandson. It is hard enough to get grandparents rights as it is in Tx. I had no idea it was inappropriate to contact a Judge. How to I justify this to the Judge that hears my case?