EOS Key Generator FUD!!

EOS token swap/snapshot/launch is coming up June 1st-2nd. Many of us have already registered, or are soon registering our tokens to ensure we get all the airdrops, and the proper placement in the snapshot.

When looking up how to properly register our EOS tokens, most instructions lead to this thread by "Sandwich"
https://steemit.com/eos/@sandwich/how-to-update-the-eos-public-key-mapped-registered-to-your-ethereum-wallet-with-myetherwallet-mew

In this post "Sanditch" links us to https://nadejde.github.io/eos-token-sale/ which is a "fork" of the EosIO key generator.
My concern here is, how safe is this 3rd part key generator, I am not a programmer, so going through the public Github code for this is not really an option.

What does the community think about all these people registering through this 3rd party key generator? Is it vulnerable to attacks/compromise? How easy is it for someone to possibly get all the private keys generated and essentially steal everyone's EOS tokens once main chain launches?

At least two prominent crypto you-tubers both are recommending people register their tokens using this 3rd party key generator. Here are their videos.