It is only deceitful if you haven't made a honest effort to improve your situation in your current company. It is as deceitful to stay silent and don't give your employer a chance to increase your salary of your position.

It depends on the type of company of course. There are those that see you as an exchangable human resource where it may be appropriate to see the company as a slave owner who has to be hidden tghe truth of your escape from.

But there are companies where honesty about work situations is seen as interest in the company and critique used as feedback to improve the environment.

Salary negotiatons will be always tough though. Strictly comparing offers is the only reliable way to sell yourself. Everything else is falling prey to the salary negotiation tricks of the business world.

EDIT: I'm from Germany so my view my be country specific.