Please tell us that you have posted this as a joke just for the cute word play. Because if that is not so, I think it fundamentally misrepresents the circumstances that Ivar has been dealing with.
The company Original Buff SA developed a lightweight elastic neck tube over 20 years ago, and coined the term 'buff' for its name. This was a fundamentally new meaning of the word in English. While the word might have been in use for centuries, it was never used to refer to such an item of clothing. As such, the company was entitled to protect the use of this term for that purpose as a trademark, and have done so around the world, together with a range of the Buff logos.
While some of us think that the word has entered common usage, others have pointed out that this is so for many other words we use in day-to-day speech that are trademarks. Facial tissues, adhesive tapes and carbonated soft drinks are examples. Nonetheless, the trademark owner remains entitled to the protection of their intellectual property, and where their trademark is used in advertising, etc, they are entitled to ask that the person who has done this to cease and desist.
Without knowing the details of how the message was sent to Ivar, the company appears to have detected what it considers to be an inappropriate use of its trademark on Ivar's website and asked him to stop using the term that they own for these items. I see that as a perfectly rational and reasonable approach to finding one's trademark being misused. Ivar hasn't let us know whether this discussion was handled sensitively by the company's representative or not, neither does he need to. But there is no reason to suggest that the company would have been other than professional in their dealings with him, even if one can imagine how upsetting and unwelcome this might have been to Ivar.
On the face of it, Original Buff SA has a well established and long standing record of owning the term and logos as trademarks. This is not something recent. They clearly advertise that the term is a trademark on their own website, and relatively simple searches of several trademark databases verifies that this is not a spurious claim.
I am not an expert in how this might play out in Spain were Ivar to ignore the company's request to stop using the term, but I can imagine it would progress to more formal demands and further legal action. That is not something that I would relish personally, and wouldn't wish on anyone else. In any case, Ivar has already made the changes to remove the term. I think we should be supporting him in that.