Plants contain natural toxins, but meat is only dangerous when it's contaminated
Whether a hazard is built into a food or picked up on the way makes no difference to the person who gets ill. What matters is how often each food harms people as it is actually bought and eaten. Both need proper cooking, and the lectins in beans are reliably destroyed by it.
A toxin that occurs naturally in a plant is a property of the food itself. Every raw kidney bean carries it, so preparation is not optional. Contamination in meat is something that happened to that particular piece and is preventable with good hygiene: uncontaminated meat is safe as it is. The two are different kinds of risk, and the plant one deserves attention in its own right rather than being waved away by pointing at meat.
The distinction is real but it does not decide anything. A risk does not become smaller because it arrived from outside the food. What a person needs to know is how likely a food is to make them ill as it is actually sold, stored and cooked.
On that measure the comparison favours plants. The lectin in raw kidney beans is a genuine hazard, but it is destroyed by boiling. Tinned beans are already cooked. Recorded outbreaks are rare and small. Salmonella and campylobacter in poultry are common enough to be expected rather than exceptional. Food agencies treat all raw chicken as potentially contaminated. In the US, salmonella alone causes an estimated million-plus illnesses a year, and poultry is among the leading sources.
That contamination is also not a freak accident of handling. It comes largely from slaughter and processing, where meat meets gut contents and pathogens spread from carcass to carcass. It is a routine feature of how meat is produced. Good kitchen hygiene reduces it. So does cooking beans properly. In both cases the safe outcome depends on preparation.
The inherent-versus-acquired line is also not as clean as it looks. Some animal foods carry hazards of their own. Liver can deliver toxic amounts of vitamin A. Some fish accumulate mercury or carry ciguatera toxin. Plant foods can be contaminated as well, often by runoff from livestock.
None of this means plant toxins should be ignored. Raw kidney beans should not be eaten. The point is narrower. A food's natural chemistry is not, on its own, evidence that it is riskier to eat. The risk at the plate is what counts.