They are Indo European, not Proto Indo European. Big difference.
Indo European is a language family.
Proto Indo European is the reconstructed hypothetical language that languages in that family descend from.
There are indeed a huge number of cognates between the descendant languages, but due to the linguistic changes and borrowings that have occurred in the millenia that have elapsed since their divergence, there are also a massive number of false cognates between them also, which likely accounts for the non flattering meanings the GGP was referring to.
Indo European is a language family.
Proto Indo European is the reconstructed hypothetical language that languages in that family descend from.
There are indeed a huge number of cognates between the descendant languages, but due to the linguistic changes and borrowings that have occurred in the millenia that have elapsed since their divergence, there are also a massive number of false cognates between them also, which likely accounts for the non flattering meanings the GGP was referring to.