Some people if not most dont feel she's pretty because she gained a LITTLE weight for a short time. She was only chubby for a short time (and she still looked cute), wasn't Yossi chubby for a longer period of time? I guess since Mako didn't show off her body very much at all some people kept thinking she didnt lose the weight. However...
Anyone who thinks Makochan isn't pretty needs to take a closer look at the As For One Day PV, The 2005 MM and Friends SuperLive, her perf of Porori with Maeda Yuki, and her PBs (specially the first one).