It's not a conservative reading so much as an incorrect one, and it's also nothing to do with v3 versus v2. The concern about v3 is that it means that companies are not allowed to use patent or hardware restrictions to do an end-run around the GPL's user protections.
The "viral contamination" FUD has been around for over a decade at least; it's nothing to do with version 3.
No, they do not. In fact, the example you gave is exactly the example given by the FSF to explain why this does not occur.
http://www.gnu.org/licenses/gpl-faq.html#CanIUseGPLToolsForN...
It's not a conservative reading so much as an incorrect one, and it's also nothing to do with v3 versus v2. The concern about v3 is that it means that companies are not allowed to use patent or hardware restrictions to do an end-run around the GPL's user protections.
The "viral contamination" FUD has been around for over a decade at least; it's nothing to do with version 3.