Is there something wrong with using present tense to talk about a specific mouse design?

The "just" in the first sentence could be misinterpreted, but that's not the part you quoted...

The comment above looks a lot like the Mighty Mouse is the mouse they're referring to when they talk about the computer they "just" bought.

Yes, they're talking about an old mouse. "just" has multiple meanings. As far as I can tell they used "just" to mean "simply", not "recently". They "just" replaced the mouse quickly and decisively, many years ago.

We could be talking to someone still in 2009, perhaps we can help them navigate the next 10 years.