The definition does not change the fact that it was not an act of terrorism but an act of someone with a mental disorder.

But great confirmation bias posting something that supports your opinion and is not based on the facts. The actual definition of a terror attack as per the english dictnary is:

"the calculated use of violence (or the threat of violence) against civilians in order to attain goals that are political or religious or ideological in nature; this is done through intimidation or coercion or instilling fear"

https://www.vocabulary.com/dictionary/terrorist%20attack

His attack was neither political, religious or ideological in nature. Neither was it premeditated. The evidence suggests it was due to his mental instability.

Please quote me exactly where I am excusing Issi's actions and call them mentally damaged?

I suggest you sharpen your reading and comprehension skills.