If they are meaning "something not from the stone age" (i.e. you need FF3.5+, Chrome or Opera of similar lineage, or IE9+) then I can understand not supporting IE8 or less. Increasingly people are deciding that it simply isn't cost effective to continue to support IE8 and its elder kin, the few lost sales that result being worth less than the cost in time and other resources committed to testing those environments (i.e. people are taking the opinion that someone using IE8 is a cost not a customer).
It is a decision that should not be taken lightly of course. I wish I could refuse to support IE6 and IE8 but our clients are large banks who really are stuck in the stone age in that regard. I assume that they fully considered the pros and cons of telling IE6/7/8 users to get stuffed before taking that path.
If you are stuck on IE8 or less then you have no choice but to vote with your wallet. If enough people do the same then they were wrong in their assessment and will have to reconsider. Given the target market, as I understand it, though: I don't think they are likely to be wrong.