If you are battling conditioning and prejudices, you're bound to run into and ought to run across 'bad thoughts' in order to get to the more objective, fair, and reasonable sort. Trying to avoid bad thoughts completely will only keep you from expanding your awareness and elevating your consciousness.
And especially if you're the type of person who absorbs and juggles other people's thoughts, constantly tuning into and weighing other perspectives and opinions, you will be sifting through many thoughts that aren't necessarily your own in order to compile or arrive at a conclusion or consensus.
Furthermore, thoughts heavily depend on your current state. You may have violent and unkind thoughts that you can later recognize as irrational, out of context, and out of proportion. When you're suffocating, exacerbated, and essentially far from being at peace and level-headed. They don't define you. If you keep them in check and eventually deconstruct them, they don't turn into a serious or even concerning problem. They might give you clues, as emerging symptoms, about issues that ought to be addressed within and/or around you, and be just that.
Let's say there's some darkness that you have and hold on to, too. If that's a part of you, rather than the whole of you, is it bad enough to invalidate you as the person that you are or aspire to become? Are you not still someone worthwhile?
So give yourself some leeway. Anybody who's done enough metacognition should realize and keep in mind that this much is natural and normal.