I'm probably dumb for asking this, but I'm wondering WHY would SQL Server prefer page locking over row locking when running DML queries.
In my specific scenario, I'm seeing in various deadlock graphs that queries that should S lock 400-500 rows are choosing to page lock instead - entering the deadlock in the first place. Note that I have not disabled row locks in our indexes. Moreover, I don't really think I'm missing indexes as the only suggestion coming from SQL are of the "create a nonclustered index on every column in this table" sort.
To be clear: I'm not asking for help on solving our deadlocks (not yet at least), I just want to understand if I'm missing something to try and foresee how SQL Server will behave.