It's not difficult to hate Riot after all the stunts they've pulled lately. Even if you're not a fan of the champions getting changed in unfavorable ways, you can still get angry at Riot for ignoring their mains. Because one day, Riot could decide your champion needs a rework, and completely ignore all your feedback just like they're doing now. Even people who don't play Morde are appalled at how his players are being treated, like the Cass fans were treated.
About Poppy specifically, we only know very little. We do know she's going to be a tank. Did Riot ask Poppy players if they wanted her to be a tank? No. Does Riot care what Poppy fans think while they're doing her rework? Perhaps slightly. Will Riot care about Poppy fans if her reworked kit is put on the PBE and they loathe it? No. They'll force it through because they've spent so long on a kit that it will go live. They've invested too much time and money into her rework just to have the fans veto it near the end.
And the worst part? They could have just asked.
"Hey Poppy mains, we're thinking of making Poppy into a tank. What do you think about that?"
"We think that's bad. We don't play Poppy because she's a tank. Don't do that."
"Even if we retain her Q and E?"
"Even then, though we do like her Q and E and hope you guys keep it."
"....Okay, back to the drawing board!"
Something similar to this actually happened near the end of season 3 with Yorick. The Rioter that was making the reworked kit was all kinds of interactive with Yorick fans. It actually got to the point where he posted two kits and had players pick from which one they liked better and why. Sadly, this process is lengthy, and that Rioter got pulled off the rework to work on the season 4 preseason. But can you imagine how much better it would have turned out if Riot did that for Morde and Cass? And others?