Not remotely comparable. Infernal intended to do it temporarily and only ad the last resort to save Limon. If Limon wasn't in heat, he wouldn't have done it at all.
That is not the same as Limon using his pheromones to make Inferna submit and mark him permanently. There was no reason or need for Limon to do that to Inferna, it's not like Inferna needed the mark or anything. It is just Limon being forceful for no reason at all
the brother is a perverted weirdo for wanting his own brother but what does that have to do with the interna x limon issue? In case you missed it, Limon wasn't truly drugged by his brother, Limon just pretended to be drugged. So, no one can blame Limon forcing Inferna to have sex and mark him on the brother. Limon is doing it out of his own volition, which is why readers are hating on Limon. He chose to do this.
Everybody hating Limon when in fact, Inferna also planned the same. It's just that Limon did the did first 乁 ˘ o ˘ ㄏ