I don't mind debating the evidence. There is no chance whatsoever that Avery is innocent; the evidence against him is overwhelming.
Let's start with the proof of his psychopathy. When he was younger, Avery participated in burning a kitten alive on a grill for fun. That is not something that he denies. His conduct reflects a complete lack of empathy. Only a psychopath would do that, drunk or sober. Any non-psychopath would have intervened instead of gleefully participating. In my opinion, animals should have the same rights as humans, so I would be fine with his receiving life in prison for that offense.
So as a starting point, we have a suspect who is a known psychopath, and
according to recent research, about 4.5% of people in the general population are psychopaths. That's about 1 person out of 22, so right out of the gate our suspect is someone far more likely than the average person to commit a sexual homicide. Let's not lose sight of that while examining the evidence.
As far as questioning the evidence goes, feel free to share your thoughts. It's fairly easy to to challenge any one piece of evidence, but when there are many pieces of evidence that you need to challenge, you have to ask yourself, "How likely is it that every one of these pieces of evidence isn't saying what it appears to say?"
Let's discuss Theresa Halbach's car. It was found in the Avery's family's salvage yard, so a reasonable conclusion is that someone with a direct connection to the property is responsible for Theresa Halbach's death. That's a fairly short list, and it is reasonable to start with the known psychopath at that address as the prime suspect.