Can requiring applicants to have access to a computer and high speed internet be considered discrimination?

No, they are NOT discriminatory. Employers are allowed to "discriminate" against employees on any basis not specifically prohibited by law: for example, private employers can refuse to hire employees for voted for a certain presidential candidate, who have tatoos, who cannot drive, employees who lack a smart phone, etc. There is no law making it illegal to discriminate on the basis of computer and internet access, and no protection for those who lack the requisite technology. Moreveover, even the laws against certain discrimination (e.g. religious discrimination; racial) allow seeming discrimination if it is reasonably related to a legitimate business purpose and there is reasonble no non-discriminatory way to accomplish that goal. For example--and to use an admittedly extreme example--a company could refuse to hire an Amish person as a traveling sales rep because he/she cannot drive and cannot be reached via cell phone; a claim of religous discrimination in this case would be rejected by the courts. So if the training program is important to the company and a minimum amount of computer equipment, internet access, etc. is required, then even if someone were to try to claim there is illegal discrimination going on (e.g. against some minority group which on average has less internet access or less-good computers; or against older employees for allegedly being less tech-savy), that claim would very likely fail because nowadays, having certain minimum technological resources, whether for training or for the job generally, is reasonable.