Changing Ethics in the Modern Workplace
Prima facie, you are absolutely right. Unfortunately, in today's world, the contours and definitions of 'ethics' have changed significantly, leaning more towards being a 'relative' than an 'absolute' attribute of an individual.
Earlier, the bottom line was what you and Nathrao mentioned—even if God gives a counter-offer, the individual would stick to his/her commitment.
Challenges in Hiring Skilled Candidates
Nowadays, from an employer's perspective, securing skilled candidates, especially in technical areas, is so challenging that many companies now offer joining bonuses, which were unheard of earlier. From a candidate's perspective, with so many options available for someone with proven technical abilities, maintaining the same level of commitment from individuals across the board is becoming increasingly difficult.
After all, the company has to run. I would have taken a different stand if it were me. But that doesn't mean others have to follow the same path. Here, Mekala/HR is bound by his/her responsibility towards the company, irrespective of what he/she would have done if it wasn't linked to the company.
Ethical Dilemmas and Responsibilities
In a way, I would equate this scenario to the one in Kurukshetra when Dharma Raja had to announce "Aswathama hathaha.....Kunjaraha" to ensure Arjuna eliminates Drona. Left to himself, Dharma Raja wouldn't have done what he did, nor would there have been any pressure on him to do so, but here he was bound by his dharma towards the Pandava Army.
The point surely is 'where to draw the line,' and that's where each one's perceptions, conclusions, and actions vary. This, I think, would be a better debate, though I'm not sure if there can be any absolute conclusions at the end of the day.
Regards,
TS