It's "spying" when you're gathering data they didn't consent to give, like mining through their contacts, scanning running processes or uploading unrelated content from their computer. The browser User-Agent string is hardly classified information.

Yeah, this is more like the used car dealership noticing that a lot of their clientele drives Toyotas. SPIES!

Analytics on the web are neither aggregate nor anonymous.

Declaring "absurd nonsense" isn't an argument.

In this case, the absurdity and nonsensical character of the 'spying' claim is fairly self-evident.

When a client voluntarily makes a request to a server, it presents a bunch of information for the server to see and consume. This information is not meant to be kept secret from the server. Among such pieces of information can be some about the characteristics of the user agent, including OS. It is disingenuous at best to call collecting such voluntarily-presented and clearly-transmitted data as "spying" on a user.

A basic requirement for spying is for a collecting party to be obtaining information that can be reasonably considered confidential or restricted. Details about the system from which you send a request are by definition of the protocol not confidential or restricted to the recipient of your request. It is not reasonable to expect a server to not look at or use information you present to it. Therefore, it isn't "spying" for the recipient to consume the information. The information might be used in ways some people(e.g., OP) don't like, but that does not make obtaining the information "spying".

I only posted this because it was the second time that day I saw "absurd nonsense" used as a comment with no additional content. It annoyed me enough the first time that it stuck out like a sore thumb the second time, then I noticed it was the same user and it was their last 2 comments.

You don't need an argument against absurd nonsense.

Better men than you have been beaten by absurd nonsense that shouldn't have needed to be argued against. ;)

I recall a woman who recently had this experience as well.

Just like those anonymous taxi fare statistics, no one ever extracted meaning from those..

The whole point is to extract meaning from analysis but not spy on personal information. Knowing which clients support what kind of SSL isn't personal, it is part of the request transaction.