I'd never heard of dbt before today but from a quick scan of that page it's clear to me what a that 'materialization' is in dbt. It's not the same as a SQL 'materialized view'; it could be a SQL view, an SQL table, a CTE, or a table with extra machinery for incremental updating.
In my experience in software it's common for similar words to be used for different concepts in different contexts. I think the dbt documentation is well done so I don't see a big issue.