I think Lucas certainly deserves all of our sympathy (as does anyone who isn't a child molester, rapist, murderer, doper, or douchebag of absolutely epic proportions who loses out on an Olympic spot in the last 5 meters). If we can't all agree on that, at least, my hope for humanity just took a hit.
I also agree with Rojo that she deserves our respect. While I understand those who say boneheaded moves don't deserve respect, I think we have to put her move in perspective. First, any woman who runs 15:19 deserves our respect for that performance; second, anyone who went from the brink of retirement to nearly making her first Olympic team has clearly rededicated herself to the sport in a way that is commendable; and third, although it's hard to remember with as good a she has been this Spring, this was Lucas's first time really being a contender at a US Championship and dealing with that pressure must be difficult. I don't think someone loses respect for failing to do so well in their first time in a leading role on that big of a stage.
Lucas is excitable, and in her excitement (over thinking she would make her first team and maybe win her first national title) she went too hard from just a little too far out. It was a bad mistake in the way she executed it, sure, but the idea of getting in front of the field to avoid falls and be able to see and cover any moves (especially ones made by other runners who have the A Standard) is a good one.
Hopefully she learns from this mistake and, as a runner who isn't new to this level of performance anymore, applies the lesson at the Trials in 2016 (and also at some US Championships, World Championships, and Diamond league races before then).
Ms Lucas has my respect, too, and I hope she earns some spots on teams and runs some fast times over the rest of her career (which I hope lasts at least through Rio 2016).