They "made it easier" in the sense that they removed a stupid procedural hurdle that forced companies to funnel money through other organizations in order to have a say.
Before this decision, if GM wanted to speak out on a particular bill or support a candidate during election season, they had to create or join a PAC or 527 (usually with a name like "The Council of American Manufacturers"), fund that organization, and then the organization had to speak in code words, urging the public to "keep issues in mind," to "support American manufacturing," and to "oppose efforts to send manufacturing overseas," while showing their displeasure "with officials who support this bill." Depending on the structure of that organization, it may not have been required to release the sources of its funding.
Now, rather than doing all of that, GM can create an ad that says "We at GM believe that X bill harms American manufacturing and will result in a loss of jobs for Y reason. We ask you to support this congressman who is opposed to the bill." GM's funding for that ad is a matter of public record.
Of those two methods, which one sounds more shady and likely to result in a corruption of the electoral process?
The ironic part is that because corporations don't want to be identified as publicly supporting or opposing particular candidates, even after this decision, most of them will still continue to use the former method. We're going to see just as much corporate involvement in future elections, only now the papers and public will blame it all on the SC decision overturning BRCA, when in reality, the problem comes from BRCA itself.
It would be funny if it weren't so infuriating.