I just reinstalled squid and dans. I browsed a bit without either, then with squid, then with dans added. Performance tanked with dans as before. The squid log doesn't really show anything interesting. I did something along the lines of
against the /var/log/dansguardian/access.log

The following very clearly shows that dansguardian spends the next 4 minutes chewing itself through a simple local newspaper webpage. It takes less than 4 seconds to load with dansguardian off, and I've always considered dans to be completely transparent and usually forget it is there. I am super curious to know why it is suddenly tanking.