Acceptance would be great, but even whether we could go any further than decriminalisation... I fear the worst.
It would be naive to expect wider society suddenly to see the light, sing hallelujah and praise the dog because of a couple of reasons. Firstly, in these days of social media and 24/7 online presence, everybody should take note of everything everywhere all the time, and if you don't provide your (ill-)informed opinion on the matter, you will be castigated. Everybody has to be authentic, yet at the same time if you don't jump on the virtue bandwagon you will get crucified. Only by lashing out towards others you can present your own virtues, whatever you think those are. The result is that you have some very vocal groups, usually online, who simply sit in their trenches, indiscriminately throwing out their opinions and virtue-tolling as hand grenades into no-mans-land without even taking the effort to at least listen to what the other side has to say.
In addition, it's the hooligan principle all over again: between the small but very vocal groups on both sides of the argument, there will be a larger group that doesn't really have an opinion about anything. Yes, they might repeat something that has been spoon-fed to them, but there is a possibility they are not as vehemently condemning of zoosexuality as that vocal minority. Perhaps they will acknowledge the double standards within human-animal relations, or disconnect the abuse stigma from zoosexuality.
So yes, it is possible non-zoo people will change their mind on zoosexuality, but if this will happen and when this will happen very much depends on how zoosexuals behave and talk about the matter. Normally, people only hear about human-animal sexual interactions because of tress-passing and/or because something went horribly wrong and either the human or the animal ended up with injuries. Witnessing only such exploitation, people don't (want to) know about animal consent, about the differences between abuse and zoosexuality (while at the same time condoning the mass-slaughter of animals in abattoirs because that is not considered abusive or exploitation). Anyway, as long as there are people out there who claim to be zoosexuals or zoophiles while doing nothing but using and abusing animals, people will find justifications to reject any initiative towards the acceptance of zoosexuals.
If zoosexuals want more acceptance (to become more common), then they will have to clean out their own house first and show the world there's a difference between them and the abusers.