My personal experience with this particular issue is right-wingers don't like it and consistently line up against it and I'll tell you why
I'm not writing off what you say, but I'll just chime in as a conservative who has a different opinion on the subject. I'm not against projects like this per se. However, this particular one seems to have drawbacks that lead me to oppose it. My primary objections are: (1) Our stupid government in this state is corrupt and inefficient. And while I do not completely side with PraXis, he is right about it not being budgeted and planned properly, leading to massive cost overruns. (2) I'm not sure the demand for high speed rail between S.F. and L.A. is significant enough to justify the cost. Great idea to connect cities, but I'm just not sure this particular idea has a lot of utility. But I'd love to be proven wrong on that point.
As to the five reasons in your post:
1. Big Infrastructure projects leave a BIG legacy and right-wingers want to refuse Obama any successful legislation.
I may think Obama is a lousy president, but if he has good ideas that will leave a positive legacy for him, that doesn't bother me one bit. But that being said, this is entirely a state project, so I'm not sure how it would be attributed to him if it were successful.
2. Most of the work on these projects would be done by union labor. Right-wingers hate unions.
Yes, I hate unions, and would prefer that this project be done by non-unionized labor if possible. But if this is a good project that is justified by the cost, and costs could be kept under control, it wouldn't bother me that union labor works on it. Honestly, I don't know anyone in my conservative circles who would be bothered by that.
3. Collectivism! Socialism! They have trains like this in Europe!
Not sure how to respond to this one.
4. Urban vs. Rural - High speed rail will only really work efficiently on the densely populated coasts (read: liberal areas)
Wait, what? I don't understand this one. It wouldn't make sense to connect rural areas by high speed rail because there isn't enough population to use it. Of course it would be to connect urban areas that are more densely populated. What's the problem with that? I'm not following.
5. Conservatives, generally, don't like change, and high speed rail will, in fact, result in a fundamental change in how we use transportation.
For me, it simply depends on the change at issue. Some change is good. Some isn't. I don't see high speed rail as a per se negative. If it ends up being useful and cost efficient, it sounds like a good thing to me.