"There is nothing wrong with being excited about exploring space. There’s nothing wrong with dreaming about setting up colonies in space either. But a colony on Mars would need to be a nearly perfectly self-contained, resource neutral system that harvests energy from the sun and is rarely or never re-supplied. That is currently beyond the reach of science and human ingenuity."
It's completely within our reach if we prioritize it over other things, namely the financial cost.
There's also the "things sometimes don't make sense" aspect of space exploration. Do we NEED a space station doing space research? No. Did we need to go to the moon? Some would say yes, but if you look at the economic incentives, the answer is no. Not everything can be boiled down to cash in versus cash out.
I think space travel is worthwhile to invest in right now. To everyone squabbling that the money could be used to help people here on earth: no, it could not, because money does not flow around in the earth in a utilitarian fashion, it flows based off of where people think they can make more money or do something cool. The people investing their time and money in spaceflight are not going to be buying rice for the hungry no matter how much of a "moonshot" space projects are.