Toxoplasma is a parasite. As any parasite, its goal in life is to take over a host and live inside of it indefinitely, ideally for the duration of its life cycle.As you can see in this illustration, Toxoplasma's primary goal is to live inside of a cat.
We can infer this because the cat is where its reproductive cycle occurs (in contrast, its destructive cycle, where its offspring are propagated at the expense of cells akin to viruses, is in prey that the cat is likely to eat, such as mice, rats, or birds).
Humans are infected obliquely, by handling cat feces (as in, cleaning the litter box). This is not supposed to be part of the natural cycle of things, because in nature, other animals do not set up artificial things like litter boxes (something that is clearly not found in nature) and clean up after domesticated versions of other animals. In other words, we are NOT a part of this parasite's life cycle. After we are infected with it, it is usually resolved naturally, because our immune system IDs it as foreign and disposes of it (unlike those of, say, birds or cats).
Rabies, on the other hand, is zoonetic, and over time has evolved around its usual means of communication (one infected animal inflicting some sort of flesh wound and infecting others) by becoming adaptive to various types of animals (not only bats, but raccoons, cats, dogs, humans, etc).
Basically, the reason why I dismiss Toxoplasma as being a cause of zombieism is because doing harm to its host is not helpful to its self-preservation (a top priority among parasites; note that Toxoplasma is an actual live organism and not a virus).
There's this thing called 'microparasitism' that defines classical pathogens (like viruses or bacteria) in terms of being parasites; it's 'micro' because their life cycles are much shorter than that of a parasite, and they usually cycle through multiple times in a single host.
The above is relevant, because if you think about it, the most successful parasite is one that can literally live in its host indefinitely (meaning, a symbiotic relationship would be the ideal; this would make survival of the host and survival of the 'parasite' self-benefiting for both parties).
Evolution tends to benefit the least harmful parasite/microparasite the longer a parasite/microparasite lives in/with an organism. E. Coli, under other circumstances, is a harmful pathogen, but when in a specific place (ideal for its own survival and that of its host, the intestines), it extracts vital nutrients in addition to having ample food, a warm enviroment, and a chemical paradise in which to live.
Likewise, Toxoplasma, when inside of a cat, does not do any physical harm to the cat. As a host, the cat provides an ideal environment in which to reproduce, and it does so with little incident. You hear about this parasite affecting the behavior of rats, but in a VERY SPECIFIC WAY: it makes them want to approach cats rather than fear being eaten by them. Why?
So the cat can eat the rat and thus allow the parasite to reproduce (the cat is the host).
Any other behavioral change, like violence, is going to make the cat avoid the rat. So, following the principle of natural selection, the parasite developed a tendency to influence behavior in a specific way for a specific end (to get into the cat).
Additionally, humans are an apex predator, at the very top, because of our ability to think and thus construct physical barriers (shelter) and weapons to kill other animals (both defensively and offensively). There's no animal that reliably and consistently eats us, so there's no reason to control us, specifically (a lower animal that is a typical human meal, like a cow or chicken, would be ideal to be a vector for infection, but not us).
A parasite has pretty much no reason to infect us other than as a host of opportunity (read: because we clean litter boxes, have other artificial behaviors, or otherwise happened to be in a position/state that made us vulnerable to infection).
Implying that something like toxoplasma is potentially a zombie parasite is alarmist, because the likelihood of that sort of adaptation being advantageous to the parasite is so low that it's almost astronomical.
For it to even develop the potential to become a zombie parasite, humans have to be regularly and consistently infected, over many hosts and over many years; this would be akin to saying that not washing your hands after cleaning a litter box is normal (which it most likely isn't; if cat shit doesn't offend a nose, then that person was probably already infected with E. Coli anyway). Remember, Toxoplasma wants to get into a CAT, not a human.