They do not believe Jesus is the Lord God.
Not true at all... while many do fall into that category, most don't. But, cheery pick through 40,000+ denominations and sects of mainstream Christianity and we can make mainstream Christianity look pretty radical. Yeshua and YHWH are one and the same!
Most do not believe the New Covenant is in effect and is just for Israel and Judah.
Definitions. If I come in faith to the God of Israel through the messiah of Israel, I believe that makes me part of Israel. This then stands in harmony with Paul saying I WAS a gentile and WAS an alien of the Commonwealth of Israel but am NOW a fellow citizen. At the least, we are like the "foreigners/strangers" who came out of Egypt with Israel. They were to be treated as if native born. They had the Torah given to them as well. And they assimilated into the tribes they traveled with making them as much "Israel" as "Israel."
Most think that they are under the law of Moses, except for sacrificing animals, as that is the only thing Jesud fulfilled
Again, definitions. You treat phrase "under the law" as one thing, when I know it to be an idiomatic phrase. The truth is, we are not under the law... we are not guilty, we are under grace...forgiven. As for fulfilled, like most Christians you treat this word as if it means "to bring an end to, abolish." So, let me show you what you definition does to Scripture:
Matthew 5:17 "Do not think that I have come to abolish the Law or the Prophets;
I have not come to abolish them but to fulfill them. (NIV)
Now here is that verse again, as you define fulfill:
Matthew 5:17 "Do not think that I have come to abolish the Law or the Prophets;
I have not come to abolish them but to abolish them.
Because you force "fulfill" to mean "abolish," Matthew 5:17 literally contradicts itself.
These three major beliefs are most dangerous.
No, just misunderstood. Causing Scripture to stands at odds with itself is dangerous, which is what many mainstream teachings, do... unknowingly, but they do.
Just take a look in the Messianic section of this forum if you don't believe me.
To that, I have no doubt. This is a young immature movement that is not equipped to touch the holy thing without profaning it. These are people who have come from mainstream Christianity who have not been taught methods of exegesis, they have no training in linguistics and semiotics, they wouldn't know a "time period source" if it bit them in the rear.... and yet they are dealing with information that requires training... discipleship. So, they become a polarizing mess that alienates friends, family, and brethren over issues THEY THINK are paramount but that truly are minutia. Does God care if one says Yahweh and another says Yehovah while another says Lord? No... He seeks a pure heart aimed at HIM!
I wouldn't throw the baby out with the bathwater, I would wait and see if God has a plan here. These people in that forum (a place I have not gone yet, and probably won't because of how volatile I already know it is) do not represent the body of work nor some things that are happening that God is currently doing. They are too wrapped up changing the litmus test from fruit production to knowledge and they WILL answer for this! (To God)
Blessings.
Ken