Then why did you cite it? I will not read your article. You have to present your argument here. So far it has failed badly, so formal questions for you to answer:
Explain why an intelligent civilization or individual would be ignorant enough to build any structure that would collapse to a neutron star (a precursor to a black hole),
FunBotan?
Explain why an intelligent civilization or individual would be ignorant enough to build any structure that would collapse to a black hole,
FunBotan?
Especially after they probably have the example of a collapse to a neutron star!
We would not be that ignorant. A large faction of our population would not be that ignorant (they at least know that black holes can be created by piling matter up in 1 place!).
Something else for you to consider:
Just piling matter up (your "spherical structure") until it collapses to a neutron star and then a black hole or directly to a black hole requires stellar masses. Those civilizations are either dismantling some stars and shipping them to their home system or dismantling hundreds of planets and shipping them to their home system. These are activities that we should be able to detect.
N.B. We cannot create a black hole by piling up all of the matter in the
Solar System. What we would get is a 0.14% heavier Sun. The
Tolman–Oppenheimer–Volkoff limit needs to be exceeded (> 2 solar masses). And that assumes there is no explosion during the formation of the black hole. Normally a star has to have 15 to 20 solar masses to form a black hole!