I've heard this too many times before. People have told me for years the dangers of butter when my great grandparents ate butter on food all the time. my great grandpa lived to be 98 and my great grandma lived to be 101. Here is an interesting chart unless someone has a counter point to this, I would love to hear it.

I have a Food Science background and margarines are basically oils (usually soy) that are made solid using hydrogen. The process can be manipulated to obtain a variety of textures from spreads all to way to hard, solid fats, flavorings added. The more solid, the more it can get stuck in your veins and cause heart problems, so read the Nutrition Facts label to figure that out. I personally prefer butter but if I were dairy or lactose sensitive, I'd use spreads.

Vegetable oils are bad because they contain very high levels of polyunsaturated fats (PUFAs). But did you know that the fat content of the human body is about 97% saturated and monounsaturated fat? Our body needs fat for rebuilding cells and hormone production. And it can only use what we give it.
Polyunsaturated fats are highly unstable. These types of fats oxidize easily. These oxidized fats cause inflammation and mutation in cells. That oxidation is linked to all sorts of issues from cancer, heart disease, endrometriosis, PCOS, etc. PUFAs are bad news.
Read more about PUFAS here.
Omega 6 issue
There’s a lot of hype about Omega-3’s and how healthy they are. But what often gets neglected is the fact that it’s more about the ratio of Omega-3 and Omega-6 fats that are critical to good health.
Vegetable oils contain a very high concentration of Omega 6 fatty acids. These fatty acids oxidize easily. Omega-3 fatty acids have been shown to reduce inflammation and protect against cancer. Unbalanced levels of Omega-3 and Omega-6 fats have been linked to many types of cancers and a host of other problems. And, as you’ve probably guessed, most Americans are high in Omega-6 fatty acids and low in Omega-3’s. But people keeping buying into labels on vegetables oils that say “a good source of Omega-3s” without realizing that they are really just making the imbalance even worse.
So be wary of deceptive marketing like this, just because something is high in Omega-3s does not mean it doesn’t also contain harmful ingredients. Having a “big picture” of the ingredients in the foods you are eating is crucial for a healthy diet.

Butter is good for people.  Margarine is not.  Vegetable oils, in general, are one of the worst foods people can eat.  (There are a few exceptions.)  Here is an article that explains:
https://www.thankyourbody.com/vegetable-oils/

Lots more information at the link for those interested.

Man you made me hungry.

I want me some sirloin steak with melted stick butter now. Margarine would do no such thing with a punch like that.

Has anyone had Wagyu steaks? I hear they are supposed to be good, but they are rather expensive. I imagine you have tried it, Jayne, as I believe you are one of the carnivore diet "heretics".

https://www.crowdcow.com/products/japanese-wagyu-ribeye-steak?filter%5Bbid_item%5D=i3rnsbwmr

Also, is it better to cook steaks in butter or tallow? I think everyone except for old people thinks butter is good and margarine is bad, so the question should be, "butter or lard or tallow?" Neither of these fats seems to have recovered from the mass media hysteria of the last century that condemned such animal fats, similar to the media blitz that promoted margarine before it was found to be supposedly unhealthy and condemned as evil by the same "experts" who are always wrong.

This coming week we will be canning a lot of butter to add to our long term supplies.  It's an excellent food for times of famine, being dense in calories and high in nutrition, but even better, it will last 5 years on the shelf.