" I think they manufactured this event simply to enhance their "influencer" status of youtube"

Yep, bingo. No matter the statutes - won't even argue them....THIS is the reason they did it. (edited spelling typo).

ADA 36.105 Definition of “disability.”
(a) (1) Disability means, with respect to an individual:
(i) A physical or mental impairment that substantially limits one or more of the major life activities of such individual;
(ii) A record of such an impairment; or
(iii) Being regarded as having such an impairment as described in paragraph (f) of this section.

(b)
(1) Physical or mental impairment means:
(i) Any physiological disorder or condition, cosmetic disfigurement, or anatomical loss affecting one or more body systems, such as: neurological, musculoskeletal, special sense organs, respiratory (including speech organs), cardiovascular, reproductive, digestive, genitourinary, immune, circulatory, hemic, lymphatic, skin, and endocrine; or
(ii) Any mental or psychological disorder such as intellectual disability, organic brain syndrome, emotional or mental illness, and specific learning disability.
(2) Physical or mental impairment includes, but is not limited to, contagious and noncontagious diseases and conditions such as the following: orthopedic, visual, speech and hearing impairments, cerebral palsy, epilepsy, muscular dystrophy, multiple sclerosis, cancer, heart disease, diabetes, intellectual disability, emotional illness, dyslexia and other specific learning disabilities, Attention Deficit Hyperactivity Disorder, Human Immunodeficiency Virus infection (whether symptomatic or asymptomatic), tuberculosis, drug addiction, and alcoholism.
o (3) Physical or mental impairment does not include homosexuality or bisexuality.


(f) Is regarded as having such an impairment. The following principles apply under the “regarded” as prong of the definition of “disability” (paragraph (a)(1)(iii) of this section):

(1) Except as set forth in paragraph (f)(2) of this section, an individual is “regarded as having such an impairment” if the individual is subjected to a prohibited action because of an actual or perceived physical or mental impairment, whether or not that impairment substantially limits, or is perceived to substantially limit, a major life activity, even if the public accommodation asserts, or may or does ultimately establish, a defense to the action prohibited by the ADA.

(2) An individual is not “regarded as having such an impairment” if the public accommodation demonstrates that the impairment is, objectively, both “transitory” and “minor.” A public accommodation may not defeat “regarded as” coverage of an individual simply by demonstrating that it subjectively believed the impairment was transitory and minor; rather, the public accommodation must demonstrate that the impairment is (in the case of an actual impairment) or would be (in the case of a perceived impairment), objectively, both “transitory” and “minor.” For purposes of this section, “transitory” is defined as lasting or expected to last six months or less.

In a nut shell

Posting your policies prior to entry is the exception. A patron, with a myriad of options to go elsewhere, has foreknowledge of the stores policy and can choose to spend money elsewhere. No one HAS TO shop in any or all stores, and there are other options.
"No shoes, No shirt, No service. We reserve the right to refuse service to anyone for any reason."

"a shopkeeper has essentially forfeited certain aspects of that right by opening a venue to the public."

Nonsense. What forfeit is a portion of your wealth to the city, state and other municipalities; all dependent on your success as an owner. The only harm that comes from the owner setting a policy to enter and shop is that the owner loses money should the potential patron choose not to shop there, but the city and state still get paid regardless. Neither the patron, nor the city, nor the state own the business nor do they stand to suffer anything by it not doing well The choice is theirs where to shop. Usually for a business turning people away is a self inflicted wound.

I wonder what Reardon would say about this?