He likely had identity crisis and mental issues, Islam permeated peoples minds more than other religions, so what happens is their beliefs and reality don't conform, so they become confused and troubled(especially those in the West), questioning Islam , reality, or both together. Then they develop an identity crisis which causes stress/anxiety/depression, and if they struggle to balance out their beliefs or get social support(non-religious), they lose it and give up. In this case, he probably feared route of suicide due to his beliefs, and went suicide by cop route. That and probably the race factor in the US might of played a role.
This is why Muslim communities in the US, need to provide support for those Muslims with identity crisis, help them deal with them and balance everything out. They, however, don't provide that support. Instead, there are groups in the mosque that remain to themselves, and the clerics are teaching people things like Day of Judgement, avoid 'bad things', lessons on how to be like the Caliphs, false projections that these people were perfect, when they weren't. It seems that way because all the imperfections of them are not told. Hence these confused people become more lost, trying to be 'perfect', increasing prayer/Quran, further separating themselves from reality, and getting more depressed.
The debate over Islam doesn't need to be had now because no one is mature enough for it yet, it is for the future. But, there need to be revamped programs, less sermons on lifestyle back in 6th century which were healthy then, not now. Religion can't be used to treat mental health, identity crisis,personal problems, exam grades, income, etc.... This worked for 6th century Arabs who were tough, lived in harsh climate, and had better mental health than most of those today, so they were able to conform to Islam pretty well initially. Today, not the case.
hey doctor what about 100s of other incident of mass shooting in the US.