Unfortunately, the author if this article picked a bad example of a case where the IRS has engaged in behavior that might be considered intrusive. A homeowners association that presents itself as a 501(c)(4) corporation has to attest to certain things when it gets its tax-exempt status. In this case it sounds like the association is going to owe a lot of money in back taxes, interest and penalties if they are lucky. The worst-case scenario is that the IRS pursues a criminal prosecution for tax fraud.
“no need for a warrant because the information is in the public domain already”
I do see your point but to me it is a distinction without a difference. They have to have a valid reason to go after information about a specific person, even if such information is low-hanging fruit.
They can’t just monitor and spy on people, looking at their patterns of spending via credit cards, their associations with friends via social media and telephone records, see what their houses look like, etc., to build a file and FISH for POTENTIAL wrong-doing. We are allowed to have privacy in our spending and associations and our homes.
Intrusion is not permitted, and the easier it is for them to do so, the more vigilant we must be to violations such as these and call it what it is — a violation of the 4th Amendment.
IMHO