I can think of many, many things that are (1) better for humanity than going to Mars, and (2) somewhere between "exploring Mars" and "building weapons."
The pithy phrase I've seen before is "let's fix this planet up before we go and screw another one up."
There's nothing we can do to "fix" the risk of an unknown/unidentified space object hitting Earth at high speed and ending human civilization other than establishing self sufficient human cities on other objects.
The article's point is not a choice between humanity's going to Mars or not going to Mars. The article makes the case for suspending the mission until we have more information and better answers as to why. These arguments in favor of going to Mars are addressed in the article.
I'm more interested in known quantities than unknown ones. Besides, I'm not the one going to Mars, nor are any of the people who I think deserve to have their lives improved.
It is a known that eventually a planet killing asteroid will hit the Earth (again). We just don't know when.
But, more importantly, it is a misconception to think that the people GOING to Mars will have their lives improved. Life on Mars will take a very long time to become as good as life on Earth. But the tech developed to make living on Mars possible will help people on Earth.
The pithy phrase I've seen before is "let's fix this planet up before we go and screw another one up."