There are two possible scenarios here:1) You sincerely believe that plants think as highly, and feel pain as much, as animals. To you, there is no hierarchy in intelligence between a human and a cow and a clam and a carrot; all are equally capable of experiencing emotional and physical pain. If this is the position you take, then there is no point in my arguing with you, as you've rejected both modern scientific knowledge and common sense. It's like trying to argue evolution and the age of the Earth with a creationist who takes a literal interpretation of the Bible, i.e. pointless.
2) You do not really think that plants and animals are the same in their capacity to suffer. If this is the case, then you are being intellectually dishonest with me for the sake of argument. Since you know that a cow or pig can suffer far more than a carrot or a bean plant, but continue to eat beef or pork rather than switch to a vegetarian diet, you've obviously made a choice: your taste for flesh outweighs your concern for animal suffering. Does this mean that you do not care about animals, or worse, are sadistic? No. It means, as I've just said, that all things considered, you are not willing to give up meat, despite what you know about animal suffering. I'm not demonizing you here, Lark, simply saying it as it is. If this bothers you, perhaps you need to ponder it.
Either way, there's no point in arguing with you, as it's clear that you've made up your mind.