So what is wrong about what I said?
Your source literally states that GBL is available for legitimate use in industry.
It never mentions anything about the possession being illegal.
Citing
wikipedia here
United Kingdom: Because of their legitimate uses, regulation 4B of the 2001 regulations makes it lawful to import, export, produce, supply, offer to supply or possess GBL and
1,4-BD, except where a person does so knowing or believing that they will be used for the purpose of human ingestion.
Germany: GBL is not listed in the narcotics law, but its distribution is controlled. Possession is not illegal, but may be punished according to the Medicines Act, when intended to be sold for human consumption or synthesis of GHB. In recent years, an increase of GBL consumption has been observed due to the prohibition of GHB.
Netherlands: GBL is unlike GHB not listed in the narcotics law,
[37] but its distribution is controlled. Possession is not illegal but may be punished according to the Medicines Act, when intended to be sold for human consumption or synthesis of GHB.
Pretty much the same across all three.
AKA if you can find a supplier that is willing to sell to you you're fine as long as it's intended for purposes other than human consumption.