Synthetic motor oil is chemically quite similar to conventional motor oil. Both are made from hydrocarbons. One is drilled from the ground, the other is made in a lab. Lab-grown meat vs. animal meat would be a much better comparison.
But you're comparing apples to oranges. Vegan chicken that tastes exactly like chicken is as good as it can get. If it tastes better than actual chicken, then you've just created a new meat-like product with a chicken-ish taste.
It's like a Charlie Chaplin look-alike contest where Charlie Chaplin himself ranks sixth. You can say someone looks almost like Charlie Chaplin, but claiming they look more like him than he does himself doesn't make any sense. At that point you're just saying you prefer the way one thing looks (or tastes) over the other. So you could equally say cake is better than meatballs.
Having opposing opinions doesn't mandate insulting the other party.