It's odd that in 2017 we are still having this debate. wiki welcomes you to improve the article. In fact that's the whole idea behind the site. It's odd that some users are still missing this use case in its entirety.
Less chance of being bitten by people who seems to think they does the planet a service by rejecting and deleting content.
I recognise this might only be a misunderstanding, I rarely get bitten myself but I have seen enough useful questions and answers being punished on SO and enough Meta discussions telling everyone how great this is to learn that the site is mostly not for me.
Welcomes? Over the years there have been many projects to make Wikipedia more welcoming to newcomers, because WP recognised that the "don't bite the newbies" guidance is nto always followed.
I don't know what it's like now. I'd be interested to see the results of surveys of new editors.
I've had edits rejected and I must say Wikipedia's 'assume good faith' policy makes it less hard on the newbie ego.
https://en.wikipedia.org/wiki/Wikipedia:Assume_good_faith
Maybe newbie edits that don't cut the mark is one of the processes that attempt to drive the quality upward.