It is indeed a problem to not have enough time. Just throwing in some facts in an article is often not good enough, it must fit with the flow of the article and

It is indeed a problem to not have enough time. Just throwing in some facts in an article is often not good enough, it must fit with the flow of the article and not repeat things that has already been said and be in order, and with references etc etc. Some people might not have the time for that additional work to make the contribution "good enough". I haven't followed Wikipedia for a while but I assume that some rejected changes are due to that people throw in some changes that might be correct but are not worked on enough to fit in with the rest of the article. And one can't in general assume that someone else will do that work for you. Than the easy way out is often a revert instead of leaving a more unfinished article live. I did most of my contributions to Wikipedia when I had that extra time.