Enemies can not only be starved out and besieged, but also pacified assimilated. Truly dangerous groups will almost always be attacked using the full force available (which we can't really hate the billionaires or the state for doing, since we do, or at least we ought to do the same right back). Groups that like to dabble or flirt with confrontation might get the stick, or they might just get the carrot of further monetary support to meet their goals, so long as there are some provisions.
This is the trap of being an actual tax exempt 501c3: There are all sorts of legal requirements to maintain that status, and then on top of that there are the requirements of funders, who will often fund things like research groups that might be affiliated with other political movements or tendencies, but that funding will be limited to strictly circumscribed uses. Even when radical action and politics aren't explicitly discouraged, there is oftnen a fear on the part of the institution and leadership of losing the lucrative funding they've come to rely on - they will start to police themselves. A good book to read on all this is "The Revolution Will Not Be Funded" edited by the INCITE Network.
I suspect that more likely than all that though is that the work of the CERSC is so devoid of any actual potential threat to the power structures of capitalist civilization as to be entirely worth funding for progressive/lefty foundations. It isn't as if the ISO is really calling for very drastic changes to how things are ordered (maintaining hierarchy, industrial production, the state, blah, blah, blah...)