I've never heard someone complain years down the line that they wished they hadn't started out simple. There are two paths that result in high success rates for new hobbyists: research extensively and for a long time before acting (which has not been done in this thread!), or go simple things and learn as you go with animals are more forgiving and better understood.
This is the "saving the animal" issue that crops up all the time in the hobby. By buying and keeping the animal, you are just ensuring that more are collected unless it was a total shipping mistake. Most stars that enter the trade are just flat out doomed for reasons like this on top of the disease and shipping casualty cases, making it arguable by many that many species shouldn't be collected for the hobby at all until they are better researched - meaning things like proper, scientific documentation of diet as was done recently for those Echinasters (which, frankly, the average hobbyist is not equipped to do).
Regarding the sale of fish and such, it's important to remember that there are two participants in the problem of animals with a poor captive record in the hobby: the irresponsible LFS that is willing to sell the animal to someone who can't take care of it and the hobbyist who pays them to continue doing it. Hobbyists are responsible for the demand existing in the first place, so the ethical issues of aquarium keeping fall on our heads first. LFS aren't all-knowing and the good ones know that and DO pay attention to hobbyists' concerns as a result. Bad stores ignore everyone and carry on; they get supported by hobbyists who don't care much about the animals or who don't know any better. The best stores even make a point of not selling to hobbyists they don't know or haven't interrogated thoroughly. If you can give the star to someplace like that, then the star will be best off if another hobbyist can't be found.
As already mentioned, you could also find another hobbyist you know to have large, mature system that has a really good chance of supporting the star. Anyway, this is my third text wall on the subject of Echinoderm ethics. To avoid beating dead horses, that's the last I'll say on it and will just wish you luck with whatever you choose to do.
