What is typical power consumption of FPGA devices
In general, the amount of power an FPGA "consumes" is related to the function it is performing and the frequency it is operating at. That's why you can't find an authoritative number; because "it depends". I suggest that you play around with the power estimation tools, figure out what the input fields mean, and then you'll have a much better understanding of the factors that contribute to the overall power consumption of the FPGA while it is running a particular design.
The power estimation tool provided by the FPGA manufactuers is a very good way to obtain an estimate. Obviously, the more information you can provide, the more accurately the results reflect the power consumption you'll see. Otherwise, there are too many parameters that influence the power consumption.
I highly recommend that you try it, even if to see what are the major factors that go into this (Clocks, number of I/Os active, etc).
The reason they direct you to a power estimation tool is because the power consumed depends very heavily on how hard the device is working.
Intel know that their processors will be clocked at the max rated frequency (at least some of the time) and that all the processing units will be used (at least some of the time).
Xilinx have no idea what their customers will do. It may be that the design is slightly too big for a small device, so needs the larger device, hence only (for example) 60% of it is used and the other 40% lies idle, not consuming dynamic power. Most time customers cannot clock the entire device at anything close to the theoretical fmax, so that reduces dyanamic power also.
If you were to calculate a theoretical max power dissipation, it wouldn't help much as you'd then end up overspecifying your power and cooling subsystems by a factor of (guessing) 2x to 4x!