Unless Bloomberg is coercing internet providers into handing over his emails and getting secret court orders to record his web traffic, it doesn't seem like a very good comparison.
Investigating people, especially those with any kind of political, economic, cultural, academic, or other influence, based on publicly available information and whatever people are willing to tell you if you ask, is a pretty traditional part of American public life. There's no right to force people to be disinterested in what you do and refrain from writing articles about it, as long as they collect the information by legal means.
I hope that's a joke. As one reply here mentions, the financial press typically avoid pissing off the rich, but I would not include Bloomberg in that list.
Bloomberg have been battling the government in the courts for years over FOIA requests to disclose secret information to the public on a variety of issues.
For example they were very aggressive in investigating and publishing details of secret dealings between the largest US financial institutions and the government during the financial crisis:
Bloomberg Sues Fed to Force Disclosure of Collateral (Update1) [1]
Wall Street Aristocracy Got $1.2 Trillion in Secret Loans [2]
Fed’s Once-Secret Data Compiled by Bloomberg Released to Public [3]
As well as publishing details on billionaires who manipulate the system from the shadows (e.g. the Koch brothers):
David Koch’s Chilling Effect on Public Television [4]
Koch Funneled $1.2 Million to Governors Battling Unions [5]
Koch’s Iran Link Causes Democrat to Send Donation to Charity [6]
The financial press rarely acts to piss off rich people. This article was probably written with the billionaire's consent. I don't know why, but I would not be surprised if they planning to take the company public.
Investigating people, especially those with any kind of political, economic, cultural, academic, or other influence, based on publicly available information and whatever people are willing to tell you if you ask, is a pretty traditional part of American public life. There's no right to force people to be disinterested in what you do and refrain from writing articles about it, as long as they collect the information by legal means.