The assumption that they're all working from the same system is where things fall apart. Even though zodiac signs seem straightforward, astrologers use wildly different methods to generate readings - different house systems, different interpretations of planetary positions, and some sites just hire writers who aren't even trained in classical astrology. One site might weight the moon's phase heavily, another might ignore it entirely. Add in the fact that some places use the tropical zodiac while others use the sidereal one, and you're already looking at different dates for where your sign actually starts and ends.
Beyond the technical stuff, a lot of horoscope sites are just... made by people writing for engagement rather than accuracy. They're optimized for being vague enough that you'll read into them, or they're using templated content that barely gets personalized. Some astrologers are genuinely trying to do the work carefully, while others are just spinning out generic feel-good or cautionary statements. There's no quality control, no peer review, nothing like that. So yeah, you got conflicting advice because the websites literally don't agree on methodology or even have the same goals. One wants to be mystical, another wants clicks, another might actually take the craft seriously.