European farmers want that grain exported to other continents instead of lowering local prices.
Or in other words: European farmers want laws to be followed as they spend money to produce to EU standards and there is no way Ukrainian grain should be allowed to be sold for most applications anyway. Of course keeping corrupt shitheads at the top from violating regulations to dump Ukrainian grain into European markets is not an option for some countries... because those guys at the top do it with full knowledge of their government buddies.