Is Netcut Dangerous?

Hello,

Configuration: Windows 8 / Chrome 48.0.2564.116

Hello everyone I just have a few questions regarding the Netcut software:

-Is it dangerous for the connection? (in short, can using this software too much ruin the internet connection)

-When I cut certain devices connected to the box, my internet speed still drops a lot! I go from 250KB/s when no one is connected to 50KB/s when I cut the other machines' connection. Is that normal?

Thanks and have a good day in this rainy weather.