A core tenet of nerd culture is fans arguing over what outsiders would consider "dumb" things. It was always who would beat who in a fight, why this would/should never happen etc.
Unfortunately, over the last decade, nerd culture spaces were infiltrated by tourists. The tourists then redefined this behavior as 'toxic'. But if dialogue is to be honest, one should recognize these are two different types of perspectives:
1. A fan and long-time customer displays their passion and care for the brand which manifests itself into disputes, arguments and fun discussion. The arguments, no matter how heated, are coming from a place of love because they care about the sub-culture. All parties involved are actual fans and have more than likely spent more money than you could imagine on the properties.
2. A non-fan hates just to hate. They are not at all interested in the brand/property/franchise. They are only interested in chaos.
Access media, content creators, and politically/socially motivated people purposely conflated #2 with #1. Often, the chaos agent spreading the idea of "toxic" fanbases... are #2 themselves.
The bottom line is this: If you think it's 'toxic' when fans argue about the universes they've invested so much in, you are totally unfamiliar with nerd culture. You're telling on yourself.