Doing repetitive skills on beam is not the same as taking repeated line drives to the head, unless you're splitting the beam and falling every time. In that case, perhaps the hesitancy and lack of surety/ confidence comes from training up before the gymnast in question was ready/prepared.
I honestly think that most of those saying this are new to this, with compulsory kids, and are including the hours their kids are doing homeschool. It sounds very much like "my daughter does more hours than yours..." type of bragging.
It was said that as of last year, they are not inviting directly from national testing. There are some kids that did get them prior to testing (by sending videos), but apparently there were complaints about not getting to go to A camp since it is paid for, and DIC isn't.
It's hard to go off of years prior to 2017 though, because more were taken to camps, and kids were being given invites to DI camp directly from national testing (bypassing A camp) except for last year. The higher scoring kids are being kept in the mix for camp qualifiers.