I use Entity Framework 7 with Npgsql adapter. Sql generated by EF seems like
SELECT \"r\".\"Id\", \"r\".\"Name\" FROM \"public\".\"Role\" AS \"r\"
FYI version 2.1 of the Npgsql EF Core provider will only quote identifiers when that's needed (e.g. when they contain an uppercase letter).
More importantly, everyone wanting snake case columns (or anything else besides the current behavior) can simply use the EF Core fluent API to manually specify whatever table and column name they want. It's also quite easy to write code that goes over all entities and properties, and automatically defines their database names by applying snake-case conversion or something else.
This is better than changing any provider service, and will always work, whereas changing the SQL generation service (or any other) could be brittle.