They support A, AAAA, CNAME, MX, NS, PTR, SOA, SPF, SRV, TXT, which is better than most. But I agree, why on Earth would they not support the DNSSEC record types? It's not as if it would have been any extra work for them...
They're probably using an open source authoritative DNS server which doesn't yet support DNSSEC. If they upgrade to BIND 9.7 or NSD they'll get DNSSEC support for free.
They support A, AAAA, CNAME, MX, NS, PTR, SOA, SPF, SRV, TXT, which is better than most. But I agree, why on Earth would they not support the DNSSEC record types? It's not as if it would have been any extra work for them...