Yes, the idea of liberty (for everyone to use free software regardless of intent) and the liberty of immigrants in the US to live without harassment and terrorism of their communities are indeed in conflict. So you have to choose one. By not choosing one, you're choosing the existing system -- ICE uses this software to accomplish these goals.
We're not trying to infringe on ICE/CBP's ability to use popular open-source software. We're simply asking some companies not to help them with support contracts.
Hope this helps!