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There is NEVER a bare virus particle “in the wild”. EVERY virus particle is either in an aqueous microdrop or (if it dries by evaporation) has a coating of salt crystals and other bio-solids. Masks filter these quite nicely.
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You just made that up. If you really believe what you are saying, put on one of the commonly used masks and stand near somebody with Ebola, plague, or any other airborne virus.

“You just made that up.”

No. I’m a scientist (PhD Chem) with a background in biowarfare instrumentation development. I actually understand this stuff. The generation of microaerosols is a critical part of understanding the subject.

Good layman’s summary of the science behind mask-wearing:

https://theconversation.com/masks-help-stop-the-spread-of-coronavirus-the-science-is-simple-and-im-one-of-100-experts-urging-governors-to-require-public-mask-wearing-138507

A second layman’s article on the science behind mask-wearing:

https://www.bbc.com/future/article/20200504-coronavirus-what-is-the-best-kind-of-face-mask

Particle sizes stopped by masks:

https://pubs.acs.org/doi/10.1021/acsnano.0c03252

Composition of saliva (the microdroplets generated by coughs and sneezes):

https://www.thejpd.org/article/S0022-3913(01)54032-9/fulltext

Size distribution of microdroplets generated by sneezing:

https://royalsocietypublishing.org/doi/10.1098/rsif.2013.0560

More about droplets and aerosols:

https://first10em.com/aerosols-droplets-and-airborne-spread/

Still more about droplets and aerosols:

https://www.ncbi.nlm.nih.gov/books/NBK143281/

And still more about droplets and aerosols:
https://www.ncbi.nlm.nih.gov/books/NBK143281/

Umm.. Ebola doesn't spread that way. You don't need a mask to safely stand next to someone who has Ebola. It only spreads via direct contact (such as through broken skin or mucous membranes in the eyes, nose, or mouth) with: blood or body fluids (urine, saliva, sweat, feces, vomit, breast milk, and semen) of a person who is sick with or has died from Ebola.

Bubonic plague spreads via infected insect (typically flea) bites. Septicemic plague spreads via infected fleas or by handling an infected animal. Only pneumonic plague is commonly spread via cough. Since they're respiratory droplets (>5-10μm in diameter), a mask would effectively reduce the risk of transmission from an infected person to an uninfected person.

The mask doesn't prevent you getting infected; it drastically reduces the risk that respiratory droplets released by you talking or coughing or sneezing make it to another person. And it doesn't filter the virus itself. The mask stops the respiratory droplets required for viral transmission.

Airborne transmission is distinct from transmission by respiratory droplets. Respiratory droplets are large enough to fall to the ground rapidly after being produced (usually greater than 5 μm), as opposed to the smaller particles that carry airborne pathogens. Also, while respiratory droplets consist mostly of water, airborne particles are relatively dry, which damages many pathogens so that their ability to transmit infection is lessened or eliminated. Thus the number of pathogens that can be transmitted through an airborne route is limited.