I think it is. I you tell me that X is bad, subconsciously i decide that i do not want X. But if Y is worse, i must chose X. Scientifically, our brains are wired to choose the easiest, most logical answer. If the options are doing something illegal, or doing something illegal and getting caught, which would you pick?
Assuming that I am limited to two options; X and Y, I have just been told that X is better than Y. This will alter my decision making because I have been told that X is the obvious choice. In summary, yes it is an endorsement because it is saying that X is a better choice.
No where in this statement does it say that I endorse X in fact it says X is bad. However if you put emotional words in instead of X and Y then some people may get riles up and not understand the rational logic behind the argument. But the proposition is very true.
Murdering a man is bad, but murdering him and his whole family is worse. So no, it isn't an endorsement of single homicide. Getting a D- is bad, but an F is worse, it doesn't mean you should get a D-. In certain situations, the equation could work, but it doesn't work as a blanket.
The objective standard of X being worse than Y doesn't actually do anything by itself. The information presented still does nothing by itself. Unless there is a clear indication of an attempt to persuade it is a non-issue.
This topic did not take fifty words so here are the rest.
First off, let me borrow a quote from Penn Jillette, who perhaps borrowed the quote from someone else: "Choosing the lesser of two evils will still lead to more evil".
Now, from a definitive standpoint: An endorsement, as defined by Google's dictionary, is "an act of giving one's *public* approval or support to someone or something". An endorsement is, by definition, a very public act.
Imagine some sort of life scenario in which you are left with only two options, or decisions. The decision termed "X" is a terrible idea, but the decision termed "Y" is even worse. With the absence of any alternatives, you will be forced to choose an option that is, at the very least, terrible. You will not publicly approve of this terrible decision, nor will you publicly support this terrible decision. But on a personal level, when left with no alternative options, you have little choice but to approve and support choosing "X".
Only when you proselytize choosing the "X" option, does it become an endorsement.
It depends on the situations.
Let's say that you have to choose between candidate "X" and candidate "Y". X isn't quite suitable for the position but "Y" is just as inept and WAY worst. Eventually you might choose the 'best of two evils'; which in this case would be "X", or not choose at all.
Albeit, given a situation where you are chosen to do a certain action such as; smoking cigarettes or taking heroin could be a different story. Sure, heroin is a worst decision than smoking but it doesn't mean that you should smoke considering that it is harmful as well.