The CEO states in the first couple of minutes that they wouldn't be supporting that kind of activity and is apparently against their terms of service. This seems pretty obviously not about freedom of speech but about what illegal activities Patreon could be accused of supporting financially.*
Does he go on later in the video to justify removing other accounts because of political beliefs? I haven't made it much further in.
*EDIT: So after watching another video on the subject, the official statement has less to do with what Patreon doesn't want to be seen funding but more about a section of their content policy stating they will not allow action that might endanger the life of another person, i.e. blockading search and rescue vessels.