lmao everyone is going full damage control and saying stuff like Touko's using her friend as a replacement for her sister and stuff
Touko was never in love with her sister. Y'all need to accept that harsh truth just like sister Rikka did
The massive similarities between the two Rikkas suggests a sister complex could well have contributed to Touko's dating her, but it would've almost certainly been entirely on a subconscious level.
When people consider a failed incest a tragedy...
It's probably more the fact that we ride Rikka-nee's emotional train from blase to "my sister loves me?" to "my sister loves me!" to total heartbreak. If the entire narrative weren't married so closely to her emotional journey, you'd see different reactions(hopefully).