Ummmmm... rental space that is being rented out is not a home office any way you look at it. Doesn't matter if it's a SCH C business. The space rented to the tenant is not, in any way, form or fashion a home office. Therefore there is no choice. As you say, "the IRS is pretty clear on that". The website you reference uses both terms of "business use" and "home office". I'm highly confident the IRS would not consider space rented out to a tenant for even a short term SCH C business, to be a home office, or to qualify for the simplified method.
An AirB&B business reported on SCH C is treated basically the same way a hotel treats it in their business. Hotels don't and can't go take a simplified deduction for every single room they rent out.
