I’m not even sure if “rec league” has to equal USEF.
I’ve personally never been a USEF member past the fan membership and even that’s not something I’ve had in the past year-ish at least.
When I was growing up - single parent household in terms of income but raised by mom and maternal grandma so not “single parent” in the “coming home to an empty house after school.” Grew up riding at a backyard barn with frankly dubious horsemanship skills, the limited showing I did was 4-H, county fair. The one and only time I had the opportunity to compete in dressage before I stopped riding for a combination of reasons, it was a schooling show over a decade ago now at the intro level and I was definitely not great at it. My OTTB didn’t have a whole lot of bend, even for intro level, I frankly wasn’t skilled enough a rider/trainer on my own and didn’t have a skilled instructor who could’ve coached me on how to really bring out the best in him (he was a good horse. Probably not like, gonna be a champ, but probably more athletic than my 19-ish YO self knew and my one regret as an equestrian is that I didn’t wise up to the type of barn I was at soon enough to move him out, but, alas, I didn’t wise up until after he died of colic.)
I don’t really, as an equestrian, even see “supporting the absolute lowest levels” as a USEF thing. I see that more as, “okay let’s get more 4-H and Pony Club and similar type programs for the youth. Let’s all broadly work to ensure people can find ways to be introduced to horses safely and learn the skills they need.” USEF exists purely, IMO for people with the means and connections to compete at that level. They can talk nobly all they want about trying to diversify the sport but they’re not the entry level, if they ever were, those days were long ago.