If it's my first suspension why is it for 4 days instead of 1?

The length of a suspension is based on the severity of the offense as well as any previous enforcement actions.

There is no set number of days a suspension will be just because it's a first offence.It's possible to get a permanent ban for a first offence if what you did was severe enough.

Hi and thanks for reaching out. I hope you’re doing well. I'm an Independent Advisor and a Microsoft user like you and I'll be happy to help you.

I apologize for any inconvenience you may be experiencing. As a friendly reminder, there is a dedicated team that handles enforcement concerns and inquiries. Unfortunately, customer support cannot assist with suspensions or enforcement actions as they do not have access to the details of those actions. In this case, I highly recommend visiting enforcement.xbox.com and checking for more information about your ban. You may also be able to submit an appeal or request a case review on this website.

For more details on how to submit a case review, kindly check out this link; https://support.xbox.com/help/family-online-saf....

Yea they were only 24 hour suspensions all 8 of them but @darkist1 they where all by 1 person and idk why I have received a week suspension in 2017 for multiple messages in 1 chat and then same situation little over 2 years its 8x instead of 1 and dont
understand why I was able to reduce the first 24hour suspension but not the other 7

The "railing" suspension would have been due to the use of profanity. Not anything threatening. Suspension length increases with each suspension. Since you had already had a 24 hour suspension that is why the 2nd suspension was 1 week.

Also, investigations do take time, so that first suspension could have been for something that took place day or weeks before that particular incident. Suspensions are not always issued the same day as the action.

One message leading to a 14-day suspension would indicate (1) this has happened before, since suspensions escalate in length for each subsequent infraction, or (2) if this was the first suspension, it was a doozy of a message, since the severity of the incident
can also determine the length of the suspension.

As to DDoS, you're right, it's not really Xbox's issue. While you certainly should report users threatening to employ such tactics, if one were to occur, you would report it to your ISP instead, since they are the ones being attacked, not your Xbox.