If they replied that they could match the asking price but after all the song and dance they actually low-ball with an offer of 60% what the candidate was already earning, which is nearly half of what they initially mentioned, then that's pretty close to fraud.
Oh yeah people love that. They're usually so thankful to have been taught a lesson about this technicality that they not only don't mind having been told the wrong thing, they instantly become loyal to that person for life. Immense profit follows.
The legal side is almost irrelevant. The situation is that they're trying to initiate what should be a mutually-beneficial, longish-term working relationship. Leading into it with this kind of letdown isn't a good start.
The hiring company just counters they "can give X" for an imminently qualified candidate but after the interview process they feel the candidate has too little experience or aptitude and is being offered a job in spite of their shortcomings and should be so happy with the offer.
"we can give X" is not a promise to give X.