We can only speculate, and different people may have different opinions. To understand the true motive, you would have to inquire of He who placed those stars in those particular places in the sky. Or else consult the ancient individuals who looked at that group of stars, decided what it looked like to them, and gave it the name Sagittarius.
Sagittarius the Archer, is right behind Scorpius the Scorpion. both visible in the summer sky - south if you live in the Northern Hemisphere.
A star chart
The constellation Sagittarius represents a centaur with a bow. Its name, in Latin, means archer. Sagittarius is one of the constellations listed by Ptolemy in the second century.
Sagittarius is a constellation in the night sky, not a physical object like a star or a planet, so it does not have a surface temperature.
It is placed in the sky because there is not enough room for it on Earth!
Orion was placed in the sky in Greek mythology to honor a great hunter named Orion who was killed by a scorpion. The gods took pity on Orion and placed him in the sky as a constellation to immortalize him.
VulpeculaSagittaHerculesOphiuchusScutumSagittariusCapricornusAqauriusDelphinus
There are more than twenty-two stars in the constellation Sagittarius. Sagittarius is one of the largest constellations in the sky and contains numerous stars of varying brightness and sizes.
Capricornus is bordered by these 5 constellations:AquariusAquilaSagittariusMicroscopiumPiscis Austrinus
Aquila has nine neighboring constellations: Aquarius, Capricornus, Delphinus, Hercules, Ophiuchus, Sagitta, Sagittarius, Scutum, and Serpens Cauda.
Sagittarius is a summer constellation --- the best time of the year is August to see it at 9pm. Sagittarius is also a Southern constellation: if you're in North America, it can be seen roughly towards the south and will not rise very high on the sky.
canis major