When you buy something, you do participate in the cash flow that makes the seller/builder company function. If that company has other activities or influences

When you buy something, you do participate in the cash flow that makes the seller/builder company function. If that company has other activities or influences that you do not agree on, boycotting is not virtue signalling, it's voting with your money. And while protesting some system from a place built with it may not be perfect, it is still better than refraining from protesting at all, if one has reasons to.