Hi,
It is only your developers who can answer you why this or that property in their code was disabled.
From your side you can say that the test tool has some requirements and if these requirements are met, then you can create more reliable tests in a shorter time period. Otherwise you will have to to implement some workarounds that will impact both tests reliability (in your case - just because image comparison is extremely unreliable and should be considered as a last resort only) and tests development time.
Hopefully, you'll have then some discussion and can make some decision acceptable for you and development.
