Why has congress created a "cooling" off period regarding lobbying?

The huge problem of lobbying is that corporations, billionaires and other wealthy interest groups use it to influence law-making that fits their own agenda at the expense of the welfare of the majority of citizens. It is an instance of institutional-private corruption. The cooling-off period was a very effective PR stunt to make citizens believe that lobbying was finally being regulated and abuses legally punished. It is supposed to discourage former Congressmen from seeking employment within lobbying agencies or other private interest groups that shape government policies and laws to fit the private agendas of major economic groups or individuals. It does this by forbidding them to seek employment with such groups for a period of a year after they have left Congress. Most of them just go ahead and take a sabbatical and become lobbyists or just go to work immediately for an interest group that does lobby but that uses another name for it and that is how they circumvent such porous rules.