Generally companies don't actually need to have 100% of their workers at the same place at the same time ready to start their day. They just like insisting on it, first because they can, it's considered an acceptable cultural norm to always be punctual and it's one of the things they can ask for unlimited amounts of without looking evil. The second reason is, for the boss, it's extremely gratifying to have everyone there at a bad time, at your beck and call.
But it's wage theft. Part of it's they want you there early on the off chance you do some work for free. If you punish lateness extremely, the subordinate has to go to extreme lengths to avoid lateness, and that eats up their time in exchange for nothing. Especially with the idea of "no excuses", which is bizarre, because that leads to the logical conclusion that you should spend every hour outside of work commuting to and from work. Every hour. Because there's no excuses, and let's take for granted getting fired is unthinkably bad (it could be), then why not wake up an extra two hours earlier every day? Or four hours? You can't rule out the likelihood that there will be three accidents on the way to work, and there are no excuses, so the logical conclusion is you have to dedicate even more hours to commuting if you really don't want to be late.
In fairness to employers, however, there is such a thing as a slippery slope where if you don't insist on showing up on time it becomes a mess and work never starts.
And I do believe that being on time every time gives you dignity if you do it for your own sake, as an employee.