Others may say that Hera is being vindictive, but she understands that she's only left with two choices now: either to let this slide or retaliate. She has keenly observed how Alice subtly attacks her, aiming to portray her in a negative light. While these attacks may be subtle, their impact is not lesser.
The other participants have already begun treating her differently, choosing to find fault with her simply because she appears to be living a better life than them in the show and because of the subtle taunts staged against her.
Hera doesn't want to blindly say that she understands them and just forgives them. Now that Alice has rallied everyone to isolate her and think badly of her, why can't she do the same?
The only difference is that Hera's planned stage for Alice was grander, and the repercussions would be more painful than what Alice had prepared for Hera.
