The oil resistance chart of LS-H1 bell hammer says that it affects rubber/plastic/resin, but does it?

The Bellhammer series basically does not affect rubber or resin used in industrial systems.
The three main effects of chemicals are swelling, cracking, and softening. Cracking and swelling are more common with chemicals that are highly volatile in balance with their counterparts, and swelling and softening are more common with products that are less volatile.