People should be aware not all Shabbos related sins are on an equal level.
Some types of activities (namely, those used to build the mishkan-tabernacle) are forbidden by Torah law and under certain circumstances punishable by the death penalty.
Other activities are forbidden by Torah law but don't carry a death penalty.
Others are forbidden by Rabbinic Law but not Torah law and therefore do not carry a death penalty.
One could argue that certain activities are forbidden because of custom (for example, the community following a stringent opinion, even though one could also find lenient views on the subject).
I would like to do more research, what is the status of someone who does basketball practice for a professional sports team on Shabbos.