Why can't people use even basic grammar in emails?

[MasonC2K]

I just received this is response to a query about incubators a guy was selling:

Yeh i have did severl ball clutches man im a big in too herping and make me a offer on both on is modifed to circulate air and i will take 60 that one and 30 for basic and that was my ole lady that email so im sorry man both work and hold heat

I may not respond back solely based on it looking as if written by a 5 year old.