OO and relational algebra are very different paradigms.
An ORM will force the class structure onto the RDB-schema.
It's only using a subset of SQL and can be mapped back 1-to-1 to an object model (of the particular host language, here Perl).
It's like a amputated creole, speaking English words with Latin grammar. But without the possibility to introduce new Latin particles to express the new grammar, forcing you to use costly workarounds.°
E.G. there is no "inheritance" in SQL.
An SQL-Abstraction attempts to express all or most of the SQL-Space inside the host language, like with a query builder.
It's effectively just a new SQL dialect, attempting to map 1-to-1 onto other dialects (like LIMIT vs TOP )
My impression is/was that DBIC attempts to have the best of both worlds, which also explains it's complexity.
For a long read why many people despise ORMs you may want to have a look at