I work in higher ed in the two-year sector and would like to address what @Momball11 posted. Schools have extensive General Education requirements for at least three reasons.
First, most higher education accreditors require a General Education program, and you can't award federal financial aid without some type of accreditation. These rules may change in the future, but this is the way the system works now. In the mid-Atlantic region, one of the rules for being accredited at any 4-year or 2-year college reads: "at institutions that offer undergraduate education, a general education program. . . offers a curriculum designed so that students acquire and demonstrate essential skills including at least oral and written communication, scientific and quantitative reasoning, critical analysis and reasoning, technological competency, and information literacy." There are other rules, but this rule is the big one. So. . . it is not as if colleges can do away with Gen Ed; if they do that, they can't offer financial aid. In the UK, for example, there are no Gen Ed requirements, and a UK degree only takes three years to attain. That's why transferring from a college abroad to an American college can be challenging, as the degrees are not equivalent. Specific states also have specific degree requirements independent of accreditation; the State of Virginia famously has rigorous Gen Ed requirements for all its institutions.
Second, General Education can offer some protections for students. At open colleges, which, like most two-year public colleges, enroll anyone who signs up, General Education ensures that all students meet certain outcomes before starting their majors. Remember, entering two-year college students may have graduated high school years ago, may need multiple mental or physical accommodations to succeed, may need to work 40+ hours per week and be close to home to support family members, or may not be confident in their English fluency. Everyone is welcome to enroll at their local two-year public school, but not everyone is prepared to succeed. Gen Ed also helps students switch majors; imagine if any time they switch majors (the average number of switches is 3), they lose ALL progress toward any degree and must start all over. Remember, the primary mission of a public two-year college is ACCESS and workforce development, regardless of level of high school preparation, SAT scores, age, prior experience, etc. Most two-year colleges have a mission that focuses on access and economic development for the local area, not just academic excellence, although many can and do accomplish both.
Third, and to the point of why partner four-year schools won't take certain credits: education is a business. The four-year partner schools want to sell those credits to your student. If the student can take all of their major requirements at the two-year college, then the four-year college has nothing to offer. Four-year colleges that are not part of a state system often refuse to transfer in student credits simply in order to make money. Even an extra semester of non-transferrable credit helps them meet their credit sales goal for the year. I think this approach is unethical, but I work at a public college. Public colleges are often required to articulate credits from other in-state public colleges; private colleges have no such requirements.
As for dual-enrollment issues, those often vary by state; however, no institution that awards a degree or diploma likes double-counting. Generally, the rule is this: you can apply something like Calc I to meet ONE requirement, either the high school math requirement or the college Gen Ed requirement, but you can't use it for both. Dual enrollment helps students who have already met all their high school requirements to advance through about one semester of college, but it doesn't replace a high school diploma requirement. Four-year schools that sell 4+1 degrees (in education or engineering, for example) often double count, but that double-counting is in the service of selling an extra year for credits for the MA or MS.
While all of this explanation has nothing directly to do with baseball, it has a lot to do with the point of enrolling at a particular place as an athlete -- education, education, education. There are many different types, and it helps to know why each institution approaches its community differently.