My impression is that a large part of the people that say this, are already quite experienced Linux users that are quite comfortable with compiling software from source. The entire toolchain that is involved is already set up on their system, and some of them probably already forgot what they had to do in order for it to make it work.
What is quite often not mentioned is that the required toolchain does not magically land on your system. If you are experiencing prolems compiling MySQL source it's quite likely the toolchain is broken somewhere.
Those that want to compile MySQL from source on Linux: please take some time to read some of the excellent advise from Jay Pipes. Although rather inconspicously titled Making a Corresponding Test Case for your Patch, his HOWTO contains very important information to set up your building environment.
For those that can't wait:
...here are the things you should have installed to avoid headaches:
* automake version 1.9.6
* autoconf version 2.60
* bison version 2.3
* m4 version 1.4.4
* libtool version 1.5.22
Note that it is important what order you install these tools! libtool must be installed last to avoid linking with older versions of the other tools. If you don't, you get weird errors.
I'm running Kubuntu Edgy, and I could get packages for all of these things, except one, Bison. I had to compile that one from source too.