Orthodoxy and Catholicism both came from the First Church (and so they are somewhat similar), which was put in place with all of its rules by Jesus's disciples, following the spoken instructions he gave them directly. Protestantism came out of the Reformation, which happened like 1,000 years after the first church was founded. Reformers basically wanted to get as far away from Catholicism as possible, because of a lot of big disagreements about certain things. So those are the bare bones skeletal basics.
In my experiences, many Protestants I have come across unfortunately hate both Orthodoxy and Catholicism. Catholicism is a lot more widespread, though, and generally accepted. I have seen some actually call Orthodoxy Satanism, and sometimes it seems like they just hate it, refuse to actually learn about what it is, and they certainly don't recognize it as a form of Christianity (my old church did not, and they knew nothing of it). Some I have known, and from things I have seen in toxic comment sections on social media, will gladly verbally persecute both Orthodox and Catholics. It's sad and shameful.
The folks I've met online here are a wonderful exception! Folks here are so much more willing to listen and learn along with me, they don't judge, and they are kind even in disagreement.