Because these groups are part of a real Eastern Orthodox church, in this case ROCOR, they're Orthodox, but they're also schisms from the real Orthodox churches of Greece, Romania and Bulgaria. Likewise the ROCOR churches in Russia. More examples of the evil of redundant jurisdictions, like the Eastern Orthodox in America since the 1920s. So my nonexpert guess is the schismatic groups are Orthodox but not canonical.
Makes your head hurt - the schismatic groups are out of communion with the Greek, Romanian, Bulgarian and Russian Orthodox churches but in communion with ROCOR, which is in communion with the Serbian Orthodox Church and the Greek Orthodox Church of Jerusalem, both of which are in communion with the Greek, Romanian, Bulgarian and Russian Orthodox churches!
There are three ways to undo or cut this Gordian knot: simply accept the Orthodox communion as is; accept the position of groups I call sincere Eastern vagantes (Old Calendarists out of communion with 'world Orthodoxy'), who like the Old Believer schism of old think they are the only true Eastern Orthodox left on earth and that the larger church at some point became a fake; or, like Fr Deacon Lance but not an option to 'de management' on this board, be under Rome and wish and work for corporate reunion with all these bickering groups!