I read the source

> Available evidence rules out natural phenomena as likely drivers, suggesting a large-scale pollution event and its associated mitigation measures most likely precipitated the declines...That the declines began shortly after the Deepwater Horizon oil spill points to that event as the most parsimonious explanation. These findings suggest that despite its immense size the deep-pelagic biome is vulnerable to human-induced disturbance and possesses limited resilience to facilitate recovery.

This means "the oil spill caused the declines". That is what this means in English.

I think you're reading the wrong motivation into this and reaching the wrong conclusion.

This behavior, being skeptical and precise, is the very thing that makes scientists more trustworthy than the average Joe with his motivated reasoning.

I'm confident that the people working on this would have made the causal claim if they had been able to collect enough data to support it. They may well be working on gathering data to support the causal claim right now.

Scientists are - rightfully - reluctant to assign causal relationships when the data does not support it.

Scientists should not change the scientific method so morons can continue to ignore or cherrypick their studies.

Because they're scientists and not activists.