Most people, when they really think about it aren't as pro-Utopian, as pro-entropy in an enclosed space / system / world, as pro-death , as some anti-Frontier universe types are.
That sounds like Lead Us To The Promised Land style religio-prophetic rhetoric to me, with the unbelievers being chastised for their lack of faith. And set up to be scapegoats to blame when the prophecies don't work out.
Humanity does live in an enclosed space/system/world for the foreseeable future and the health of this world is essential to the continuing technological advancements that might make space colonisation achievable. I don't see my doubts that colonising space is achievable without extraordinary technological advances as "pro-death" or that I am anti-frontier, just realistic about what is achievable and opposed to wasteful expenditures based on overhyped and unrealistic expectations.
There are good Earth based goals and reasons to advance space technology, including very ambitious ones, such as meteorite defense that could be widely supported despite no innate profitability. Asteroid minerals for Earth use have commercial potential, although we appear way short of being able to do so, but if it can be done I don't doubt there will be large scale investment.
As I see it further advances is space tech do not depend on grand long term goals like colonising space but if the tech that can support them does emerge there won't be a shortage of interest.
I think making human colonisation of space a high priority is premature. I think if it happens it will be an emergent outcome of activities in space for other more pragmatic reasons and getting ahead of ourselves won't make it happen sooner.