It may seem stupid, but having it stay that way is likely a strategic choice.
Having something closed source means that exploits in your code will be found less frequently.
If something was open sourced, both ends benefit. From it being faster to find exploits for one, and the other simply being faster to patch. This would result in a more resilient system over time, at the cost of more exploits initially.
In Roblox’s cacse, it’s a double edged sword. Giving WineHQ maintainers the list of functions that would trip anti-tamper, would allow for support of Roblox, however, it could inadvertantely provide malicious actors with insight into how the system works, which could potentially lead to more sophisticated ways of evading detection.
This presents a dillema for Roblox Developers. Either restrict access to Linux entirely, which would conserve resources, or add support to Linux, potentially costing roblox even more to combat more sophisticated exploits.
I’m sure some staff working at Roblox would love to add Linux support, and may firmly agree with you, but I’m also sure that the “Roblox corporate team” may view it as a waste of resources, and see the associated risks as unjustifiable, considering the menial potential revenue they’d receive from Linux users.
Maybe once Linux gets a bigger fanbase, with people more willing to stay on Linux and not Dual-Boot just for one or two games, we’ll see further support, but that’d only be when Roblox sees the Linux as a platform for profit.