> People just hate being told what to eat - it's as simple as that.
In Netherlands in loads of restaurant the vegetarian option will taste terrible. In recent years that's slowly changing. I often wondered why someone chose the vegetarian option, it looked and tasted terrible. It wasn't just the initial impression, everything vegetarian was bad to terrible. Plus stupidity on my part, instead of buying something nice that's vegetarian I'd try terrible meat-replacements.
To me someone eating vegetarian was someone giving up enjoying food.
IMO it's nicer to focus on the positives rather than on what someone cannot or should not do. E.g. various colleagues are now vegan. Some just because the vegan diet is better for them (more energy, sleeping, etc). That's stuff they experienced, I'm not vegan/vegetarian.
Another thing I realized is that sometimes the meat part in a dish is actually terrible. A lot of the chicken in Netherlands is sold with a huge amount of added water. It actually does not taste any good, sometimes it is not even noticeable that it is in a dish. A vegan friend was visiting, I already was doubting why I was adding chicken to a dish. Replacing the chicken resulted in a nicer dish (cauliflower with mango chutney plus loads of other spices). Since that experience that dish will at least be vegetarian.
Further, why not let people experience it? Instead of saying that they'll change, maybe say it might happen. IMO it's not that important someone completely changes their diet or never eats something. If they go from regularly eating meat to sometimes eating meat that's already a huge change.