"Why is it not the right time to discuss this issue right after an incident occurs?"
It also results in a rush to "pass something" -  without the careful consideration that solves problems.

"Why is the issue always blamed on mental illness even when there is no sign of mental illness?"
Do you think that senseless mass shootings like this are committed by sane people?

"Isn't it strange that many legislators who are so concerned about the mental health issue are also voting to cut funding for mental health services?"  "If mental health is such a major issue, wouldn't it seem like additional funds should be appropriated for that purpose?"
As a former paramedic, I can tell you with 100% certainty that the biggest problem is that law enforcement is not sending people in for evaluation - even when they have profound symptoms.   this could have stopped several of these mass murders.  This problem must be solved first - than we can and should evaluate the need for more resources.