[dandraper]

As with any secure system, it depends on your threat model but the early versions of OPE are woefully insecure. The attack you're describing sounds like the one on the Boldyreva scheme from 2009. While all OPE schemes leak some information, the more recent schemes are much more secure and often quite appropriate for many use cases (arguably at least).

ORE has different security properties, particularly Lewi-Wu 2016. There are also now hybrid schemes like the EncodeORE scheme of 2020 which is both more efficient and more secure than previous OPE and practical ORE schemes.