How can I disable the View as grid/list buttons in Magento 2.1?

You can choose the Catalog view option as grid only or list only. The default is Grid/List. You can change it to List/Grid as well.

To do so:

1) Go to Store -> Configuration -> Catalog -> Storefront

2) Change the List Mode.

If needed can be also applied from layout xml


<?xml version="1.0"?>
<page xmlns:xsi="" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
        <referenceBlock name="product_list_toolbar">
            <action method="disableExpanded"/>