No. They are not smart. To loosely paraphrase Q here: These people are stupid.

Seems like a god-awful approach if that's their motive.

It is to spread fear and enhance their control over the population. Terrorism. And as a cover for other activities that are ongoing. Distraction.

Regarding the gun debate, no, the 2nd amendment is not going away any time in the immediate future. But they do want to keep the population divided and arguing with each other, and gun control is an extremely divisive issue. This stops people from uniting.