The problem isn't the actual controversial subject of the show.
Of course this will cause reactions and objections.
That is why it is controversial worldwide.
When you attempt to deal with such a serious subject (and there is none more serious than human life itself) you must build a very strong and solid foundation with a clear objective and absolute seriousness in dealing with it.
The main problem with the series is that they never managed to live up to the seriousness of the subject, and furthermore successfully stick the BL theme to it.
On the one hand there is a suspicion of seriousness and at the same time the protagonists are for the most part suspicious of each other rather than in love.
To such an extent that it is humanly impossible to believe the romantic part of the story or be driven to thoughts about the main subject.
They are two rivals, with different beliefs in such fundamental principles and values ​​that in the end, the supposedly romantic part of their story, diminishes the seriousness of the matter and their relationship becomes unbelievable.
When you want to deal with such a topic, you must know very well what exactly you want to say and what to achieve.