EDIT: the two questions are asking the same thing - does X exist. I wonder if the light question should be voted to close.
are you getting at the difference between "product existence" and "product recommendation" being a very fine line?
I have some sympathy with you, and I've mentioned this in the past (probably > 1yr ago). There is a school of thought which says that asking whether a product exists is identical to asking for a product recommendation, and I'm not sure I'd go along with this. But whatever, we don't seem to be very consistent.
I suppose the safety net is that five people need to agree that it is a product rec before the question gets closed. (That's assuming it isn't closed by a moderator, who will close unilaterally, because that's how the site works.)
Incidentally, when I mentioned it I was told that if I disagreed with the closure, I could always vote to reopen the question. Obviously this option is available if you have sufficient rep, although whether it is futile or not, I didn't bother finding out.
I think rather than just posting a couple of links, you should write down your thoughts on this.
The problem with bicycles is that a lot of the things are somewhat proprietary, so you do have to talk about specific products. If its non-trivial to find the answer with a quick web search, and others can objectively use the result, I wont't vote to close.
For example, there was a question on mounting V-brakes and I specifically mentioned a Mavic product, and there are maybe 2 products on the market which do that functionality. I think it was a good question that does have some aspect of product rec to it, but I don't think it should be closed.
Another example, if you want to replace a rear derailleur and its a 10 speed road Shimano system, you can put in a certain set of Shimano RD's (or Microshift as well, technically, though nobody does).
On top of that, some parts tend to be relatively specialized, e.g. in the lights question.
I personally draw the line depending on the broadness and repeated utility. If its something super wide (e.g. is this bike good, find me a hybrid i'm 5'11", etc.), I'll vote to close because its a pretty opinion based question which you can get a million answers and doesn't help anyone else.
On the other hand, with the lights question, its quite niche, theres a few specialized answers and if someone else has that problem, its great for them to look it up there. Moreso, theres something else in that lights question, in that the reason for non-existence.
In short, I'm reminded of this XKCD:
If it takes some thought to fill it out and it involves specific products, thats fine with me. If its something you can find by a quick google (example: selecting a hybrid, you can go to BikeRadar or somewhere and read some reviews), I'll vote to close.