There is no statistical evidence that mentally ill people on SSRIs are more violent than mentally ill people who are not on SSRIs.
There is zero evidence that either Ambien or Xanax makes people violent.
I agree that normal people do not just murder people in cold blood for perceived slights.
Ivan Lopez was not normal.
He pretended to have a medical condition he did not have - as you correctly pointed out. Normal people do not do this.
Not only did he claim PTSD, he also claimed to have a TBI for which there is no record.
His social media footprint indicates his morbid tastes, but does not indicate that Islam was one of those tastes.
Let's be rational and apply Occam's Razor.
There is no evidence that he was interested in Islam. There is plenty of evidence that he was a nutjob.
Obviously these a$$holes are mentally ill but it seems that a fair number of them are on ssris, ritalin and/or other psychoactive drugs. Maybe they would have done what they did without the drugs. Maybe they all ate carrots that day or used Charmin bathroom tissue.
I personally had a bizarre reaction after being given Ambien in the hospital after major surgery. The only way to describe it would, I guess, be an LSD trip. Truly bizarre and horrifying. The nurse told me that that reaction was not uncommon.