Not automatically - Tofu isn't as good as fish regarding the fats, and while mercury is unlikely in tofu (or other accumulating poisons), all soy products can have other really nasty contaminations, depending on the origin.
Well, everything can have nasty contaminations, depending on the origin
Especially most of our supermarket meat (antibiotics just as one example).
There is a noticable lobby against soy products for a few years, claiming that soy is (generally) unhealthy and causes cancer. And it really works, altough the claims are mostly nonscientific nonsense. Because people blindly believe everything. But the scientific conclusions always did and still do look different. Especially cancer research as related to soy consumption for humans. Small animals in laboratory experiments simply don't count, and are not considered therefore. That a dog can be seriously harmed by chocolate does no mean that chocolate does harm humans. That a wildcat can be seriously harmed by soybeans does no mean that tofu and soy milk does harm humans.
The valid health concerns regarding soy are basically related to medical products (highly enriched), not to soy as a food. It's often mistaken in the media. Not only the German Cancer Aid recommends soy food as part of a healthy nutrition more than ever. And the latest meta-analysis once again revealed that soy does not cause but prevent cancer (
http://ajcn.nutrition.org/content/94/6/1575.abstract).
One another common misconception these days is that if one eats no soy, one is not or less affected by genetically modified soy. In fact 90% of the worlds soy crop is used for factory farming. This certainly also contains most of the genetically modified soy, which just adds to the antibiotics in the meat and ends up on our plates. Not to mention that soy meanwhile is in lots of foods these days anyway. And you have no chance to verify the origin of all the soy.
Especially if you eat meat and other animal products you are more affected by soy with unknown origin than a vegan who eats no soy products at all