Your point is valid, no doubt for me. Caesar may be improved in presenting the details of calculation. For example, the "G" factor is still within "the black box", as I know- and this really makes hard any checking.

Of course you are right about ASCE 7- it is just a building code, and the logic of implementing a minimum pressure was because there are surfaces where, under the prescriptive loads, you would have a pressure close to zero or negative that may not produce the worst case counting the total lateral force for stability analysis. That's why it is required a separate case considering the minimum design pressure.

But it is worst than you presumed and maybe you would find useful to study the ASCE Code.

Starting with ASCE7-10 the wind loads are ultimate loads, rather than service level loads. The value of minimum design pressure raised from 10 psf (pre ASCE 7-10) to 16 psf exactly for this reason.

Here B31.3 would be improved. Up to ASCE 7-10, things in B31.3 were clear.
For example, B31.3-1984 said "The method Of analysis may be as described in ANSI A58.1 or the Uniform Building Code", B31.3-2008 said "The method of analysis may be as described in ASCE 7".

But starting with B31.3-2010 the statement is "The analysis considerations and loads may be as described in ASCE 7".

In my opinion, when working with ASCE 7-10 or -16 as reference (where the loads are intended to be ultimate loads) , the solution would be to consider the combination loads according 2.4 Load Combinations for Allowable Stress Design, where you can see 0.6W as term. Does not make sense? May be a part of the "analysis consideration" under ASCE 7-10 or -16, why not?

As a detail, that would recover the same value as previously in ASCE 7 i.e. 10 psf as minimum design pressure. At this pressure level, for a rigid part of piping, wind speed must be about 36 m/sec which is about 80 mph and note that this is 3-sec gust basic wind speed (for other meteorological reference you must correlate the value, for example this is about 67 mph as fastest mile wind speed). Anyway, I find the value reasonable.