Let's look at the context starting at Hebrews 1:5 where the writer is quoting Psalm 2:7. Although the angels as a group are called the "sons of God' in the Old Testament (Genesis 6:2; Job 1:6; 2:1; 38:7), no angel ever is called "Son." The Father, however, calls Jesus "Son" at His baptism and at the Transfiguration.
God promised David a son who would establish David's house, throne, and kingdom forever (2 Samuel 7:13, 14). And David knew about it and looked for a greater Son than even Solomon, (Psalm 89.) The last part of vs5, "I will be a Father to Him, And He shall be a Son to Me?" This is a rhetorical question that is not meant to be answered.
In vs6 the Son is called "first-begotten" (prototokon). Paul said Christ was the first begotten or "first born from the dead" (Colossians 1:18). The Apostle John wrote the same at (Revelation 1:50. Here "firstborn" is an expression meaning Christ's resurrection from the dead, in a permanent way.
Prototokon refers to either superiority in rank or first in time. Hebrews 1:5 spoke of Christ as the "begotten" in a quote from Psalm 2:7. The Father said to the Son, "This day have I begotten thee," but the statement refers NOT to literal birth. Rather, it points to a position of rank.
God later declared of the Messiah, "Also I will make him my firstborn, HIGHER than the kings of the earth" (Psalm 89:27). Here, "firstborn" suggests being "supreme in rank" rather than "first in time." In other words, God would make His Son as the Messiah higher than all other kinds of the earth. Hebrews had a similar message as to His being superior to angels. This also eliminates Michael the arc angel from being Jesus Christ as you JW's teach.
So, the short answer to your question which is, "Why does God command his perfect and loyal Angels to worship his firstborn (Hebrews 1:6)?" Because Jesus Christ is God who became flesh. (John 1:14). Plus the fact that His own Father calls Him God.
Hebrews 1:8, "But of the Son He says, "Thy throne O God, is forever and ever, And the righteous scepter is the scepter of His Kingdom." Also notice Hebrews 1:10, "And Thou, Lord, in the beginning didst lay the foundation of the earth, And the heavens are the works of Thy hands." This is perfectly consistent with Isaiah 44:24, John 1:3, Colossians 1:16 and Revelation 3:14.
Lastly, I find it interesting that the founder of the Jehovah's Witnesses Charles Taze Russell said the following in the 1879 Watchtower (pg 49) that Jesus should be worshipped by the angels and that includes Michael. It's in the middle of the page.
https://i.imgur.com/y6dOdXe.jpg