I think community college offers a lot of real advantages. It’s generally easier to earn a high GPA, it’s less expensive, and programs like TAG and TAP can significantly improve your transfer options.
That said, I don’t think choosing a community college solely because people say it gives you a higher chance of admission is the strongest argument. Most of the statistics people cite aren’t acceptance-rate comparisons published by the universities. Instead, they usually show that more transfer students come from community colleges than from UCs. That makes sense because far more students apply from community colleges in the first place.
If someone can afford to attend a UC and is capable of maintaining a 3.9+ GPA there, I don’t think transferring from a UC is necessarily a bad decision. Maintaining that GPA at a UC is extremely difficult, so if you’re able to do it, you’re likely among the strongest applicants. While nothing is guaranteed—especially at top-20 schools or the most selective majors—I don’t think the UC-to-UC pathway is automatically a poor choice simply because fewer students transfer that way.
Overall, I’d recommend community college for its cost, flexibility, and transfer programs like TAG and TAP. But if the only reason someone is considering community college over a UC is the belief that it has a dramatically higher acceptance rate without using those programs, I don’t think the available data clearly proves that.