Thank you all.
So, why keeping an expression like "While the bitcointalk.org administration does not verify such claims," ?
Bitcointalk has a Trust system on this forum. We have marketplace here and people do many trades. It's impossible to trust someone online blindly but at the same time trading is a very important part of our life. In order to solve that problem, Theymos came up with the idea of implementing a trust system on this forum. Over time, Trust system evolved as the number of scammers increased. There is a list of people who have been trusted for years and are considered to be trustworthy because they earned this reputation through thousands of trades that they have done here. There are companies that register on this forum and create an ann thread. In order to fight against scam and ponzi companies, the default trust people can open flags if there are solid proofs that this or that company shouldn't be trusted blindly. That's why you see a red flag warning on their threads. Bitcointalk doesn't take the responsibility to directly tag these accounts or companies as scammers but with the help of default trust system and people who are in DT, Bitcointalk warns you to be more cautious.