I mean, the author literally posted that it was comments like this that made them want to step back yet... you still came and left one. Saying stuff like "forced to romance" "the author just abandoned" and "feels like a punishment" is quite literally over the top,  not true and those types of accusations do nothing but make authors in general feel less motivated to write. They're WIPs for a reason.

Option 1: If a platonic route is that important to you and you just want to "enjoy the story" and this Author and how they've decided to write their plot is keeping you from doing that; your best bet is playing something where romance is not basically one the biggest parts of the game. 

Option 2: Be patient. Be considerate. Wait until Zinnia gets to the platonic route (if there will be one ). Nobody is "forced" to do anything. You are actively making the personal decision to play something making you unhappy.