Let's be fair and call it copyright infringment then. Presently, most things are copyrighted the second they are written, & a copyright notice is not required. Copyright is violated whether you charge money or not, & whether or not you listed proper credit to the work's creator. Postings to the internet are not granted to the public domain unless they specifically state that, & it doesn't grant you any permission to copy them to other places.
The stories you copied belong to the authors who wrote them, & unless they gave you permission, you had no right to distribute them. While the authors can't profit from these stories without removing all recognizable characters, the stories themselves still belong to the people who wrote them, & they retain the right to do with those stories as they wish. They post them online so other people can enjoy them, not steal them & post them somewhere else without authorization.
That's exactly what you've done here. What's worse is that reviews and page hits are all these authors get for their efforts, and you have essentially denied them that by posting their stories under your own profile. Did you forward the votes and comments you received to the authors who deserved them? I doubt it. From what I've been told you knew enough to ask some authors for permission, but when you didn't get it, you simply decided to post anyhow. Yes, you absolutely stole these stories.
And let's address this statement about how everyone now needs to be glued to computer chairs. Plenty of fanfiction readers and writers alike access websites every day via cell phone. Aside from having to type a couple of extra letters into the web address, I hardly see how that requires them to be inconvenienced. The readers can still enjoy these stories on their mobile phones, just as I do on a daily basis. I've been accessing fanfiction.net and twilighted.net on my phone for over a year. Not having these stories on Wattpad doesn't change that.