Corporate welfare, in context, is the tax breaks that states, counties, school boards, and local governments offer to businesses that are willing to locate their facilities within the jurisdiction.
Democrats are resentful of these incentives, largely because most Democrats have never actually had a job in the private sector or run even the tiniest company. If they had had any meaningful experience in the private sector they would understand that Business is IN BUSINESS to make money, and these incentives are usually the rare Win-Win situations where the business is incentivized and the governments that provide these incentives ultimately collect MORE in taxes than they would if those businesses had chosen to locate elsewhere.
To illustrate, when we were looking to buy our previous home, looking at building lots in new subdivisions, the subdivision that we chose was one that could offer a two-year abatement of school taxes to anyone building within that subdivision. It saved us more than ten thousand dollars after we bought the house, but we ultimately paid almost a quarter million in school taxes to that same district, that we would have paid to another school district without that tax break.