Melania's not going to create policy --- that's hard work. Taking credit where credit isn't due will suffice.
And, "lovely" to co-sign legislation into law without the authority to do so? We truly are living in interesting times 
I just co-signed with my son so he could buy a car. He could not have bought the car without me. That is not what Melania did. Absent her signature, it was still signed into legislation by President Trump.
I personally don't have a problem with someone else adding another autograph to something they had championed, but reasonable people can disagree.
Either way, this is probably a discussion for a different thread than the one devoted to fashion choices.