If you can argue that the line is between animals and plants, then someone else can argue the line is between animals and humans.
See, this is where you are just throwing your hands up and giving up on an sort of ethics. Because it's theoretically possible for plants to feel pain then there is no reason to act moral when it comes to animals who we KNOW feel pain.
It's like saying "porn with adults is harmful, but so is porn with children, who is to say where the line is? It's an open question that is all perspective, so consume whatever you like". When we know for a fact that sexual abuse of children causes suffering as opposed to what consenting adults do for a job.
Saying plants feel pain is motivated reasoning to call vegans hypocrites, not to actually produce a better world. I did not message you with my beliefs, you messaged me with whataboutism. 99% of the food humans eat is living in some sense (aside from minerals like salt), yeast in my bread is alive in some sense, but comparing that life to an animal as a reason it may not be matter? That it's all perspective? Well then why not draw the line around cannibalism of anyone under a certain IQ. If consciousness is such an open question, then who is to say anyone is real except for myself? If I hurt another human, who is to say that they feel at all? It could all be simulation from a certain perspective so who cares?
This sort of "what if" and "it depends" whataboutism doesn't actually help anyone. I didn't bring veganism to you, you brought this to me. This is just naval gazing because calling vegan hypocrites makes you more secure in your own choices. You're not saying anything of value,