**So I believe it's most likely she did it, and that she should quit hanging about and leave the sport alone, and that Schumacher coming out all guns blazing in June and then hiding from all media and questions ever since is cowardly and bad for the sport.** However, this is my genuine attempt to put myself in BTC athlete shoes and answer the question: why have no BTC athletes have come out and criticized SH? If you want to skip to the conclusion of my answer, just go past point 4.
1) The low hanging fruit answer is "well 'cause they're in on it." I mean, sure. Still seems unlikely; it's a massive group in sheer number of athletes and has very high turnover, complete with people leaving feeling quite comfortable speaking negatively of the group (Quigley). If Schumacher were running a full blown doping system for years involving 40+ athletes, I believe there'd be way more smoke. Look how much smoke there was at NOP just with the "grey area" stuff with L-Carnitine and thyroid meds, let alone nandrolone and they were a way smaller group (more people = harder to keep things under wraps). With US Post there were years of rumors picked up by investigators and the press. BTC has basically zero beyond Houlihan. And not only has he kept all whispers to zero, but has successfully fooled all but one test out of the quite literally 1100+ USADA tests his group has gone through in history, not counting WADA/AIU tests or non-US athlete tests? To me it's most likely Houlihan snapped at some point and decided for whatever reason that she needed a boost. Seems way more plausible than the alternative. There are way way too many people who would have had an opportunity to stick a knife in the team's back across the years to assume they all passed it up. NOP had a small army of people willing to spill dirt on Salazar while Armstrong was brought down by old teammates, and yet no ex Schumacher athlete has said anything, even the ones who seem to have an issue with the group.
2) Okay, so if they're not all dirty, what gives? Well, if she's lying, then maybe it's as simple as they believe her. She's clearly good friends with a lot of the team, it's very possible they truly believe everything she says, or if they don't think it was the burrito, that maybe she got it elsewhere. How many people do you know who have been in relationships where they were willfully ignorant of their partner cheating on them for months, or even years? It happens every day.
3) Peer pressure. It's quite possible the team doesn't actually all agree on this, but a significant enough majority of the team falls into group 2 (believing her), that they don't feel comfortable speaking out, publicly at least about it. It's been less than a year since SH's ban became public. Some athletes, Schweizer, Cranny, Frerichs, plus the coaches, have been extremely outspoken about supporting Houlihan. Peer pressure sounds weak, and it kind of is, but I think in combination with number four it explains more.
4) Commercial/Institutional Pressure - There are several components at play here. BTC came out all guns blazing attacking the AIU and WADA. There's no way in hell that a corporation with Nike would let multiple employees/contractors (I believe it is the latter not former), shoot from the hip like that on such a touchy issue without giving at least tacit approval for BTC to attack like that. That means there are people higher up at Nike who for whatever reason are "Team Houlihan." These people likely have a big influence, if not full say on who gets contracts, how good those contracts are, and who gets reduced. Add to this, that Nike have been noted numerous times in the past having contracts contingent on athletes being affiliated with X group. Also consider how USATF were fully prepared to instate Houlihan into Trials even after her ban was announced only stopping after WA, WADA, AIU, and many athletes collectively freaked out. There's clearly a lot of clout still backing Houlihan.
So why have no BTC athletes have come out and criticized SH? I think there the majority of the athletes fall into category 2 - they believe her. But I also think it not just possible but also likely that there are some who don't, but for reason 3+4 haven't said anything *publicly* so far. How eager would someone be to publicly attack a former teammate if most of their friends and co-workers would hate them for it, and it would likely lead to them losing their job and gaining the animosity of a multi-billion $ corporation and federation administrators who have both shown a willingness in the past to be vindictive and litigious. Further, if I am right on point 1 and it was just Houlihan doping herself, what is publicly calling Houlihan a liar going to achieve for you other than making you feel like you have the moral high ground. If Schumacher were actually cheating somehow, it would be different, but if not then losing your job and your friends seems a high price to pay just to say "I think Houlihan is lying, I have no new evidence, but I don't believe her."
I'll point out that until CAS published its decision, the track and field community only had Houlihan's own account to judge off of and many people bought it. How many BTC athletes have actually supported Houlihan since that report came out? And I mean explicitly like Cranny and Flanagan after the BU races, not implicitly "well they're still with the team so that means they support her."