> Not sure what this guy's credentials are

He retired as a Major in the US Army (he’s also a Colonel in the California State Guard, but that's less of a qualification) after 24 years of infantry service, including two combat tours in Iraq, and he is the chair of urban warfare studies for the Modern War Institute at the US Military Academy (West Point). [0]

So, when it comes to urban warfare, he probably has some idea what he is talking about.

[0] from: https://www.ausa.org/people/maj-john-w-spencer-us-army-retir... except for the State Guard rank.