I know, it is funny too cause she did what a "responsible" parent should do; compared to Sara who basically has offered her daughter to Akira.
You could maybe explain that on the fairly significant age diff Sana has on Rin.
They are vastly different situations.
Rika is just regular parenting, which no one can fault her for (although it is hard to believe she didn't search the rest of Akira's phone, like it's actually
uncanny that one wouldn't in that situation - it borders on bad writing).
What we do fault her for is the Selebus decision of ignoring Rika for basically forever and making her first significant event be cockblocking Rin and Akira, something we've been waiting for for years.