I'm sure if you actually looked at their full track record, the vast vast majority of projects probably result in "mediocre but workable" systems, you just don't hear about them because that's a boring headline. Deloitte is a $40 billion company, it's not like every single one of their projects is a complete failure.
I've worked with many database technologies and many data professionals. I don't recall any instances offhand of technical critiques of Oracle. Pricing and business practices are a different story. Oracle the database is fantastic technology.
In my opinion, pricing is a part of the product. If one company can produce a banana for $1, and another company requires $1,000 to produce a banana, that second company is an outright failure. The banana still tastes great.
When Oracle was born, there weren't many alternatives for a high-performance and production-ready RDBMS. For a long time, Oracle was technically superior to most/all other options. That is less true now.
On the other side, if you get $10,000 of value from a banana, both vendors are viable options. If there is any reason at all preventing you from adopting the $1 banana, you're still better off buying the $1,000 banana than you are scorning it for its price.
Surely their track record should see them permanently disqualified?