I disagree, and SQLi is not simply prevented by avoiding user input. There are many cases where you need to use user input for a SQL query and its a valid pattern, and can be done securely with Prepared Statements or Parameterization.
Using an ORM discourages you from writing SQL queries and it also automatically parameterized queries. This is a good thing! In fact, from experience, the single easiest way to mitigate a naive developer from introducing SQLi is requiring them to use an ORM. People should not be constructing SQL statements by hand today, its too easy to mess this up. SQLi shouldnt be a thing in 2019, but, it is.
My point is it is VERY MUCH not orthogonal, its very much related. Avoid naive SQLi, use an ORM. Directly related.
ORM builds on top of mechanisms for prepared statements or parametrization.
Yes, ORM API can perhaps limit developers to such an extent, that they can't construct SQL themselves, and thus can't make the mistakes leading to SQL injection.
Using an ORM discourages you from writing SQL queries and it also automatically parameterized queries. This is a good thing! In fact, from experience, the single easiest way to mitigate a naive developer from introducing SQLi is requiring them to use an ORM. People should not be constructing SQL statements by hand today, its too easy to mess this up. SQLi shouldnt be a thing in 2019, but, it is.
My point is it is VERY MUCH not orthogonal, its very much related. Avoid naive SQLi, use an ORM. Directly related.