I cite my source again ... draw your own conclusions:
That would not be a problem if they made that clear, i.e. cited IPFS as a source. And as IPFS is an open source, free software project, they can use the code like they want while respecting the license.
But for whatever reason - maybe simply negligence, but it would be worse if they intended to pretend they invented key IPFS concepts - they omitted to cite the IPFS paper as their source. In most countries, all texts with some originality are copyrighted. If you cite larger sections of an original paper, you must refer to the source, otherwise it's plagiarism and illegal.
In contrast, Ethereum's whitepaper mentions Satoshi's Bitcoin paper several times and cites it correctly, like it's standard in the academic world.
But it seems that they copied different things from several other projects not just one:
https://bcfocus.com/altcoin/tron-trx-developers-plagiarised-code-from-other-crypto-projects-researchers-allege/16077/
''They apparently plagiarised code from Ethereum among the other projects and then changed filenames. It was done so that identifying the source of the code becomes difficult''
That seems pretty shady to me.