I don't think there is any evidence of this. Open Source tools fully support Lattice (low end) FPGAs, and support for Gowin FPGAs is not quite as mature.
It seems that many of the initial FPGA patents have expired, and that's why many small FPGA vendors are appearing. Please correct me if I am wrong.
I agree. IP theft is a bold claim, that is why I was asking for more citations.
Not only are the patent expired, but there are three projects that generate FPGA fabrics programmatically. FPGAs are extremely easy to construct as they are a repeating lattice.
