When server-side localization is used Filtering is always enabled.
Runnable sample is available in ticket 1580765
The Filterable.Operators automatically configures the messages for the string, number, date and enum operators based on the resx files.
Filtering for the TreeList is always enabled.
Filtering for the TreeList should be configurable irrespective of whether localization is used or not.
After the TreeList is initialized call the setOptions method and disable filtering:
$(document).ready(function(){
var treelist = $("#treelist").getKendoTreeList();
treelist.setOptions({
filterable:false
});
})