No, my belief doesn't make anything. However, what everything is sources my beliefs, so the incomprehensible complexity of life shows that opportunities, such as for parasitic mechanisms like viruses to hijack cellular machinery to reproduce, which is what viruses do, are eventually taken advantage of. Life is incredibly ancient, shown to have begun before ~4bya. In that time it is not credible to state that such mechanisms haven't arisen to take advantage of the available niche.

It's comparable to stating that if the government issues EBT cards no one will claim them. The nature of biological mechanisms, their literally inconceivable complexity, makes such parasitic mechanisms inevitable in time, and there's been far more time for such mechanisms to arise than is necessary to make such event certain.

In favorable conditions bacteria can reproduce asexually every ~20 minutes. Each reproductive event has a small chance of going slightly awry, which occasionally produces mutations. You can do the math regarding how many mutations that generates in 4B years, but with any plausible degree of error in replication that is more mutations than there are possible species on Earth. That many opportunities for relatively short chunks of RNA or DNA that happen to encode instructions to replicate statistically guarantees they have arisen.

It's not a list of genetic code of viruses, or the tiny subset that cause disease in people. It's not much of a philosophy, and certainly not nihilism. It's just acknowledging that things happen when opportunities to happen arise, and the extraordinary complexity of biology has created so many opportunities for self-replicating parasitic mechanisms to arise it's just inconceivable they have not. Taking that statistical certainty in view of the easily reproducible evidence in our own DNA of relic fossil viral DNA that is stated to exist by entire industries of specialists that have specific expertise in the field and agree on that evidence - even without the voluminous other evidence of viruses that exists - is enough to convince me viruses are real.

YMMV

Edit: I want to emphasize the word 'industries'. I'm not talking about AN industry, but a plethora of them, many of which depend on completely different kinds of products based on using the viral form to create economic returns. From vaccines to CRISPR, from bioweapons to food additives, mechanisms found in viruses are used to produce products that make money. I don't know what you call a philosophy that simply looks at what exists and acknowledges that it exists, but that's the philosophy I ascribe to.