I am not sure why you evos make such a big deal over this. Whether evolution states that we have a common ancestor with chimps or apes or whether we descended from them is a trivial difference to make such a big deal over.
It is quite obvious that you are using that trivial difference as part of your Clinton like scorched earth policy to discredit someone as a liar who is saying something not that different from what your are saying and focusing on a trivial difference rather than dealing with the common descent assumption directly.
I can't speak for other scientists, only myself.
In the science I do I have been trained to root out errors as well as I can. I hate mistakes, both in my work and in other's work; and have an even lower tolerance for deliberate falsehood. A scientist who engages in deliberate falsehood is finished.
That is why, to me at least, it makes a difference between monkeys and apes. I know when monkeys split off the line which eventually led to humans (in fact, New and Old World monkeys split off at different times).
When scientists approach a subject, it is natural that they try to correct any errors that others make as well. And when they are deliberate errors, perhaps done to denigrade evolution, it just makes it worse.
Hope this explanation helps.