I haven't railed on them in a way that I haven't railed on anyone else who dismisses an idea/question because of the origin of the idea/question rather than it's merits. When I rail on the right for dismissing ideas from the left just because they're from the left, I brand them with the same label.
Unfortunately, plenty of people are mindless anti-Trump bots. They are irrational. I've been saying this since he announced his candidacy - that people need to stop writing him and his ideas off just because he spent the 2nd half of his career on reality t.v. But they didn't and because they didn't take him seriously, they're spending their time now trying to come up with explanations for why they were so wrong.
I see the wall the same way. Trump said it so the knee jerk reaction is that it's implausible followed by arguments to justify the emotional response. But, imo, if you stop and think it through a wall is an effective deterrent if you can find a way to do cost effectively. That's the premise of this hypo - assuming that if could be done without a financial issue would it still be a good idea. So I answered it.
AS for people who would oppose a Kasich wall being the same as the people who would oppose a Trump wall - sure, if we're referencing people on the left who are anti-everything aimed at reducing illegal immigration, except increased business penalties. But since Trump is the one who said it, we're dealing with the specific anti-Trump shallowness of thought.
And a wall wouldn't hurt families. They can simply pay to enter legally and visit their families...like everyone normally does. As for the economy, if you're referencing the effects of illegal labor on the economy...perhaps it is beneficial to the nation, in the long run, to reduce those effects. Cheap, illegal labor might be a barrier to innovation.
Ultimately, if there's plenty to discuss other than the money...people should discuss it rather than blanket writing it off because of a barrier that may/may not be manageable.