Convictions are for crimes
They aren’t being accused of any crime because there is no criminal code for speech in the United States
They have been found violating the terms of their visa and they shall be deported.
Discussion
what are the terms of the visas?
The relevant one appears to be “no material support (including dissemination of propaganda) for US designated terror orgs”
Unlike American citizens, visa holders are allowed to remain in the United States only conditionally, and can be deported for violating visa terms - including speech that qualifies as support for terrorism - even without a criminal conviction. Immigration law operates separately from criminal law (8 U.S.C. § 1182(a)(3)(B), § 1227(a)(4)(B)).
Because deportation is an administrative, not criminal, proceeding, the burden of proof is lower, there is no right to a jury trial, and no right to a public defender.