Priorities
Re: There are a lot of good reasons for sending people
It took 15 mins for Neil Armstrong to walk down 3 steps, yes, a human can "think from themselves" and do stuff outside their programming, but it's not as good as you think, there's no way that a human could cover 8 miles in a week, are you suggesting 8 days outside? imagine the radiation sheilding, oxygen/waste/CO2/water recycling, they would need just to survive, let alone do anything practical, carry equipment etc.
Robots move slowly to ensure that they don't break anything,drop down a hole, get caught on a rock etc. do you honestly think that astro's are going to risk their lives by running around for hours, miles from their habitat where a simple rip or crack in their suits will kill them?
There is a very stong argument for better robots and cameras that see high resoloution 3D images but we can develop that cheaply (tihis is what we should fund)
Even if a human sees something that a robot missed or discovered a fault that a robot couldn't identify, lets not overstate how much could be done, they won't have a magic toolkit or any resource they don't carry (and they don't carry anything they don't think they need to) the shuttle's heat sheild was fixed with a record-breaking space walk using a resin which the knew they might use, they were trained for it, yet it was still a fantastic achievement pushing their abilities to the limit (it's not like locking the A-Team up in a fully stocked garage you know)
Re: Short term, blinkered thinking
Yes, you have to begin now, but you don't need to actually send people into space to do it (yet)
1. Computer modeling can help hugely
2. Unmanned flights that monitor conditions (especially radiation) can be done in far higher numbers
3. Deep sea environments can provide most of the testing (recycling air, water and food, remote control, video etc.) this technology works well, we just need to make it lighter.
Re: Obviously hasn't thought about Einstein's limit
"All those lost landers and malfunctioning orbiters could easily have been fixed and put back into service if a human crew had been available nearby, with a resulting cost saving of millions of dollars."
Could they have been fixed? really? you would need to have sent a spare for every bit which may have broken (so why not just send another rover?), do you honestly believe that having a "crew" nearby would have been cheaper? I wonder how they got there? do you think it cost more, or less than the rover that they were fixing? I'll spell it out slowly for the hard of thinking, you can send many, many, many more unamanned craft, further and more cheaply than manned craft
Re: One world: Break it and your species is extinct
True, let's do all we can to keep it alive, does anyone think that humans will be living on the moon or europa in a completely sustainable way anytime soon? sending people into space doesn't help with this anyway, this is just the transport method, it's the e"Eden" style biodomes which will tell us if this is possible and this is the technology we need to prove.
OK, let's suspend disbelief for a few mins and assume we can establish a colony on another rock somewhere:
1. How would you shuttle that many people out there?
2. How would you shuttle the biodomes out there?
3. How many people could you sustain? enough for a decent gene pool? who would you send first? only able bodied? the best breeders? the smartest? the biologically strongest? only people who reside in the country sending them? how would you feel about the people left behind?
4. It is impossible to recycle everything (how about the machines you need to use to recycle things etc.) even Eden "consumes"
"If humans have not established a permanent, independent existence off the Earth by then, it will be the last hurrah for Mankind. Those who argue against Man in space are fools, at best, and greedy ego-centric solipsists, more likely."
To those who argue for Man in space thinking that this will save humanity instead of fixing a perfectly good planet which is not beyond hope, I have no words. Man is space OK, do it, but not until we've fixed Man on earth.