Obamacare doesn't create a disincentive to work. To be more precise is removes one incentive to work. And no, this is no mere semantic difference. One incentive that keeps some people either in their current job or in the labor market in general is the risk of themselves or their family facing a catastrophic health care situation without insurance.
One might note that abolishing slavery also removed a powerful incentive to work, namely whippings, torture, various deprivations and in some cases death. We could also incentive people to work by threatening them with the loss of their children if they did not hold full time jobs. But in a capitalist economy, the primary incentive to work is supposed to be money, not the risk of being prevented from purchasing a life saving commodity. Even the more mundane deprivation of health insurance is not so much an incentive to work as a sort of torture or extortion.
It's also important to note that this is not principally about working to get money to buy insurance. It's needing to operate in a health care insurance system in which the ability to purchase insurance is not only tightly tied to employment in general but in many cases to particular jobs if you have some condition or genetic tendency that makes no one else want to hire/insure you.
Let's put the point even more precisely, the issue is the inability of many people to purchase health care coverage at reasonable rates and/or without massive exclusions without a job that allows you to participate in a group health plan.
Cutting that chain between employment and access to coverage allows some people to retire early, leave the work force, start their own business, work as an independent contractor. It allows people to make that el dorado thing, rational economic choices. There's nothing wrong with that. Chaining people to particular jobs on the threat of losing access to health care is simply wrong.