GMO can introduce proteins into foods that would not otherwise contain them, which could be life threatening to people with food allergies. This is a concrete reason to require labeling.
> Does Piriform's request have merit?
Did you read the article they are complaining about? It reads like a how-to to rip off Pirform's data. The subtlety of winapp vs. winapp2 may have gotten lost somewhere. But statements like "The Open Source disk cleaner Bleachbit takes advantage of this as it can import all of CCleaner’s cleaning locations." sounds like a real problem.
Is this a poorly worded article or is the author suggesting taking Pirform’s proprietary data? Does your organization support/encourage people to take Pirform’s proprietary data for use in BleachBit?
The winapp2.com site seems to list a data file from Pirform, not the community. This may not be your responsibility, but it certainly puts the whole community into question. How closely aligned are you with that community?
> What is a good response to avoid any ugly situation?"
I would expect you to be an expert in these tools, this market, and the winapp2 community. The fact that you are asking us these questions suggests you are not. Do you support the article? Do you support the use of anything proprietary to be used by BleachBit? Does the winapp2 community support anything inappropriate with Pirform's data? You should take a position on all of these items. Even if what you are doing is technically legal, how you present yourself can attract unnecessary trouble.
> Do I need a lawyer?
Who knows. So the only safe answer is "Yes". But, this is as much of an image issue as it is a legal issue. You might need a marketing person to explain this as much as a lawyer.