It is nonsense. Y'shua is NOT an angel per se. Yes, in Exodus 23:20-22 we see Him referred to as a Messenger, but there is a major difference between Y'shua and the angels.
For one thing, Y'shua (whose Name means "YHWH is Salvation) is the ONLY Divine Being who has YHWH's Name within His own. Messengers, on the other hand, have the name EL in their names (Micha-el, Gabri-el, Rapha-El). In that Exodus passage we are told that unlike every other "angel" He could forgive sin, "for My Name is in him" and that Name is YHWH, the Name above all Names including that of the angels (Hebrews 1, Philippians 2:6-11).
Yeshua was the Thought before he was the Word and the Word made flesh (John 17, Revelation 19:13) and He was with YHWH from the beginning and thus was YHWH. Isaiah 53:1 tells us He was "an arm" of YHWH.
God simply is and always was, and when He sent His "Son" to be our Final SIN Sacrifice, He was actually sending a part of Himself - a human vessel with a divine Nature. Yeshua was the "arm" of YHWH (Isaiah 53:1) It is that Divine Nature inside Yeshua that lived on after His human body was killed. In other words, Yeshua basically "put a face" on God temporarily to explain YHWH to mankind from a more "personal" level.
And take a look at Philippians 2:5-11:
Philippians 2:5 And think you so in yourselves, as Y'shua the Mashiyach also thought; 6. who, as he was in the likeness of Elohim, did not regard it sinful to be the coequal of Elohim; 7. yet disinherited himself and assumed the likeness of a servant, and was in the likeness of men and was found in fashion as a man; 8. and he humbled himself and became obedient to death, even the death of the stake. 9. Wherefore, also, Elohim has highly exalted him and given him a name which is more excellent than all names; 10. that at the name of Y'shua every knee should bow, of (beings) in heaven and on earth and under the earth; 11. and that every tongue should confess that Y'shua the Mashiyach is YHWH, to the glory of Elohim his Father. (AENT)
FOOTNOTE: More than his literal birth name Y'shua (which was and is a common Hebrew name), and more than the perfect reputation that his name represents. Y'shua bears the Name of YHWH, the "name above all names"! Y'shua has the Name and reputation of the Father YHWH in him (John 17:11) and the name means "YHWH is Salvation" (Matthew 1:21). (The angels, for instance, only have YHWH's title of ELOHIM within their names: GabriEL, MichaEL, RaphaEL....)
Yeshua was divine only because He had His Father's Divine Nature, which is how He was able to be perfect enough to be our Final Sin Sacrifice. YHWH caused him to grow inside of a human VIRGIN whose hymen was ruptured "from the inside out." But we must remember that Yeshua in his human form did not come to replace the Father in any way.
Although we aren't sure exactly when YHWH created angels, and the Bible does not specifically say, it was likely done before He created the physical universe. For instance, Job 38:4-7 describes the angels worshipping YHWH as He was creating the world: “Where were you when I laid the earth's foundation? Tell me, if you understand. Who marked off its dimensions? Surely you know! Who stretched a measuring line across it? On what were its footings set, or who laid its cornerstone - while the morning stars sang together and all the angels shouted for joy?”
We know for sure that angels/messengers existed prior to the Garden of Eden, because Satan, who was formerly the angel Lucifer, was already present in the Garden in his fallen state.