Ignore the spin, get the facts, no humans in space thanks.
1. Manned space travel inspires people?
Without a doubt, but those people would perhaps otherwise be inspired by jet fighters, deep sea exploration etc. or even just plain robot "manned" craft, all the people who would otherwise be inspired wouldn't suddenly give up on life and spend their time watching Trisha and having pizza delivered.
2. People in space would be "better" than machines
Anyone who had seen the high definition, uncut, unedited version of the moon landings from the original tapes rather than the ropy TV broadcast would realise how long it takes a human to do anything at all, just exiting the craft and going down three steps took about 15 minutes. If an unmanned craft gets broke, learn from it and send another one, you can have lots of unmanned craft or go far further for the price of unmanned. (note, the analogy with deep sea exploration and "rovers" is blindingly obvious here)
3. Name one thing....
Yes, NASA did invent a lot of useful stuff, but remember it's the people who worked for NASA who did this, not the magic of space travel (let alone manned space travel), most of these things (you could argue all of them), would have been invented sooner or later, besides imagine if cancer or disease research had the same funding what suffering in the world could have been avoided?
And besides, how beneficial are these so-called benefits really? non-stick pans wear out whereas a stainless steel one could last forever (but be a little harder to clean and need a bit of skill to use), stainless pans are far more ecologically friendly. Baby foods developed from NASA technology means that people buy expensive, calorie intense, processed foods in wasteful packaging instead of additive free meat and veg cooked and blended by their parents.
4. Homo Sapiens vs. Robo Sapiens
No, that's just plain stupid, let's not think about living on another moon or planet because ours is getting screwed, lets put the technical and financial resources into keeping ours alive, besides, it's not the imaginary world of Bladerunner, can you possibly imagine the resources required to put even 0.0001% of our population onto another celestial body? (that's forgetting the weakened gene pool, eugenics argument, social elitism etc)
I'm not against (unmanned) space travel per-se, the global communications systems that we have in place are wonderful, and perhaps the helium-3 research means we could mine the moon for cleaner energy for earth, but lets get our priorities right, see through the political spin, who's life world be worse off without PTFE? who's could be better if we focused the research elsewhere? (the answers are nobody, everybody's)