The issue is that your comcast modem is acting as the gateway for your internal network. I recommend you redesign your network around the ex2200 to act as your L3 core router so that you are't relying on a $50 cable modem to route your internal traffic. The other option is run a routing protocol on the EX2200 and the cable modem or put a static route on the cable modem to tell it the loopback subnet (the /32) is on the 2200.
You cannot assign a loopback interface to a vlan, it is a virtual layer 3 interface that is always in an 'up' state and meant to be advertised by a routing protocol.