In order to understand the Ophiuchus conundrum, you have to first understand the difference between tropical astrology and sidereal astrology. Most western astrologists practice tropical astrology, which is based upon a fixed, permanent map of the constellations as they appeared in the year 0 A.D. and when the sun passes them on its way around the Earth (via Seven Stars Astrology). Western astrology also ties the zodiac to the four seasons, aligning the first sign of the zodiac (Aries) with the spring equinox, which marks the first day of a new sun cycle.
Sidereal astrology is an ancient practice with deep dies to Indian and Hindu culture, as detailed by WellBeing. It bases the zodiac signs on the constellations themselves and tracks those constellations in real time rather than referring to a fixed position from a point in the past. It is fringe sidereal astrologists who have shaken up the world of astrology by including Ophiuchus as a zodiac sign. The vast majority of sidereal and virtually all tropical astrologers agree that it is not a legitimate sign and does not belong in either system (via Keen).