There are stronger and weaker words, but using weaker words isn't always bad.
Using strong words all the time would be as bad as using weaker words all the time, as it wouldn't distinguish when something is less severe.
In addition, contrasting strong/weak words shows what the reader should focus on more.
Consider the two sentences:
John stared at the body on the ground, his body numb of all feeling.
John watched the body laying on the ground, not feeling anything.
Those sentences both mean the exact same thing, John was looking at a body, and he didn't have any feelings.
However, the first sentence would make the reader think that John is pretty horrified by the body, and he doesn't know how to react, whereas the second sentence would make the reader more inclined to believe that John is simply remorseless.
The first sentence shows John having a visceral reaction, his body has gone numb because of what he has found. You can imagine the following sentence is that he goes round the corner and vomits in disgust. Try putting that idea after the second sentence, and it doesn't work.
Obviously I'm reading a lot into these short sentences, but without context you can read each one differently. If you expanded on them more, neither one would be wrong, but in order to make the reader understand what you're trying to say, subtle differences in the language can say a lot.
That's one of the things that I love about writing. Lots of things can be said with very little.
Edit: I just realized I never actually answered the question properly, so let me bring it back to that.
You say that strong words elicit strong feelings in the reader. Whilst generally true, I would say they portray strong feelings in the character. As the story unfolds from the point of view of the character, the reader generally has stronger reactions through the character having stronger reactions.
In my examples, the first would focus on the character having a strong reaction to the body, using stronger words to describe the scenario (numb I would say is a strong word, as it implies an entire lack of feeling, as opposed to John feeling something/anything. Stare is also more intense than watch).
The second would focus on the character having a weak reaction to the body. With some expanding, this could cause the reader to have a strong reaction, for example if the reader discovers at this point that the character they are reading about is remorseless about death, and leads to the conclusion that John is a psychopath.
Descriptions using weaker words can cause stronger reactions in the reader. It is all about the reader understanding how the character sees things. So stronger descriptions do not necessarily always mean better descriptions, accurate descriptions are the better descriptions.