Stabbed to death or shot dead is -for the law- the same wrong doing

Carrying a firearm while committing a felony often carries a 5-10 year minimum, and using it can be 20-life, seperate from the crime of murder.

The reason for this is that carrying guns while committing a felony is significantly more dangerous. Same with going 35 in a school zone in an SUV vs a bicycle.

Vespa but that's irrelevant. The point of the punishment is to not have people text and drive - not to punish them for having a larger vehicle.

Many laws exist to reduce risk and harm. The difference in risk and harm of a speeding car vs. a speeding scooter should not require elaboration, as shown also by you choosing the Vespa.

The Vespa driver is not less morally culpable for ending up in the accident in the first place - just luckier that the consequences were less severe.

If we accept that the risk and harm involved in a Vespa crash are less severe than a car crash, there is absolutely a difference in moral culpability. If you knowingly perform an action where the potential outcome is the death of some random person, you should be held responsible to a higher degree than if you knowingly perform an action where the potential outcome is a handful of bruises on a random person (I'm talking about general rules, not saying Vespa crashes don't involve more serious risks).

Same reason why breaking traffic laws on a bicycle generally carries less severe punishment than doing the same on a motorcycle or in a car.

Would you make the same argument for gun violence? If a person commits armed robbery then should someone who used a .22 get a lesser sentence than someone who used a .45 ACP and if not, why? Larger caliber is more dangerous exactly the same way a larger vehicle is.

No, because the person carrying the firearm made a decision to put other people's lives on the line. A .22 can kill a person, and the person carrying it knows this, yet chooses to use it to threaten someone.

The reason texting and driving has a less severe punishment than DUI is because it represents a greater risk to the public and thus there is greater incentive to stop it.

Would you make the same argument for gun violence?

If there was meaningful data that one was more deadly, but I seriously doubt a 22 is meaningfully less lethal when you're within arms reach of the victim.