[yocto] why yocto downloads files so hard?!!

[ali hagigat]

The download rate of my Internet connection is about 100KB/s and
sometimes up to 300kB/s.
When Yocto struggles to download the Linux kernel it first starts with
many packets but after half an hour it becomes so slow and it gives up
and downloading even a simple Linux kernel fails with
errors(do_fetch() functions fails)
My questions is that an operating system can download a Linux kernel ,
for example a tar.gz or bz2 version, after about 10 minutes but Yocto
sticks to a git server and starts exchanging packets which never ends.
Why git server?!! Download the Linux kernel by its compressed tar.bz2
or tar.gz files, why git? so slow it will be
Even Yocto does not show how much percent of that file has become
downloaded!! a big weakpoint.....
A chain of downloads and bitbake program does not give any information
of its present do_fetch(), how much of that file has become downloaded
and how much is left. A never end sequence of the computer packets to
that damn git server!!