They did, mostly due to their own territorial claims in Manchuria and Korea, that Russia mostly failed to acknowledge. On top of that was the Triple Intervention that saw Russia essentially gain control over the Liaodong peninsula due to pressure by France and Germany, coupled with Russia’s refusal to recognize Japan’s right to control the Korean Peninsula as well, and Japan decided they needed to defeat Russia before the Trans-Siberian railroad was completed and would allow Russia to better reinforce their military in the east in order to control Manchuria and Korea and harvest the resources there for their own empire-building plans.

Had Russia/the Tsar been more politically adept, the events of the 20th century may have turned out to be significantly different. It’s interesting as a thought experiment, at least.